Police in Northern Ireland have released CCTV footage of the riots at a Derry housing estate that led to the murder of journalist Lyra McKee.
The 29-year-old was wounded after a single gunman opened fire in the residential area. She was taken to hospital and died a short time later.
Investigators believe more than one person was involved and are treating it as a terrorist incident. Officers think a group calling itself the New IRA may have been responsible.
In the video released this evening, Ms McKee can be seen standing beside an armoured police car and attempting to capture footage of the riots.
A man wearing a balaclava and brandishing what appears to be a gun is seen using a nearby building as cover. He is later seen pointing the gun from behind the wall.
Before making his getaway he is seen picking up what may be bullet casings off the ground. He is joined by another man in a balaclava who also picks something up off the ground.
Vigils in memory of Lyra McKee were held in Derry, Belfast and Dublin this afternoon.
Speaking at the vigil in Derry, Ms McKee’s partner Sara Canning said she had lost “the love of my life.”
"Our hopes and dreams, and all of her amazing potential, was snuffed out by a single barbaric act," she said.
"Lyra's death must not be in vain because her life was a shining light in everyone else's life.
"And her legacy will live on in the light that she's left behind."
ACC Mark Hamilton says a murder inquiry has been launched & appeals to anyone with information to call police. A single gunman fired shots in a residential area and as result Ms McKee was wounded. Tragically she died from her injuries. pic.twitter.com/Y2CSmkPfl2
— Police Service NI (@PoliceServiceNI) April 19, 2019
"Fear, hate and cowardice"
This afternoon, the Taoiseach Leo Varadkar described the murder of Lyra McKee as an act of fear, hate and cowardice.
Her killing has seen cross-party and cross-border condemnation.
"On behalf of the Irish Government and the Irish people, I want to extend my condolences to the partner, family and friends of Lyra McKee who was killed in Derry last night.
"An activist and journalist, she changed our lives as she lived - and will do so again in death.
"Twenty-one years ago today, on Good Friday, we as a people, North and South, chose peace, power-sharing and ever-closer co-operation.
"We will not be dragged back into the past.
"There is no place nor any justification for political violence in Ireland, or Northern Ireland today.
"This was an act of fear. This was an act of hate and this was an act of cowardice.
"Those who carried it out, do not share the values of our nation, nor our Republic - and we reject them.
"And so, this was an attack not just on one citizen, it was an attack on all of us, our nation and our freedoms.
"I want to express my solidarity with the people of Derry today.
"We stand with you as strong as your walls, and for as long as they stand.
"I want to acknowledge the work and the bravery of the PSNI and the emergency services.
"I echo the call that anyone who has information should come forward so that justice be done."
PSNI Assistant Chief Constable Mark Hamilton said a murder inquiry has been launched.
Mr Hamilton told a news conference: "We were in Creggan, carrying out a search operation and a public order situation developed in Fanad Drive.
"This public order situation saw over 50 petrol bombs thrown at the police, two cars were hijacked and set on fire - then unfortunately at 11 o'clock last night a gunman appeared and fired a number of shots towards the police.
"A young woman - Lyra McKee, 29-years-old - was wounded.
"She was taken away from the scene in a police Land Rover to Altnagelvin Hospital but unfortunately she has died.
"Therefore we have now launched a murder inquiry here in the city.
"We believe this to be a terrorist act, we believe it's been carried out by violent dissident republicans.
"Our assessment at this time would be that the New IRA are most likely to be the ones behind this, and that forms our primary line of inquiry".
The PSNI has appealed for information from the public.
Please assist our investigation into the murder of Lyra McKee by uploading any footage you have to the Major Incident Public Portal via the following link: https://t.co/EL93YAAEMB pic.twitter.com/RNUlztCJre
— Police Service NI (@PoliceServiceNI) April 19, 2019
Leona O'Neill, who was at the scene, said she called an ambulance for Ms McKee.
She tweeted: "I was standing beside this young woman when she fell beside a police Land Rover tonight in Creggan #Derry.
"I called an ambulance for her but police put her in the back of their vehicle and rushed her to hospital where she died. Just 29 years old. Sick to my stomach tonight."
Ms McKee was born and reared in Belfast city.
She worked as an editor for California-based news site Mediagazer, a trade publication covering the media industry.
She had written for many publications, including The Atlantic, Mosaic Science and BuzzFeed News.
She extensively covered the Northern Irish conflict and its legacy.
In 2016, Forbes magazine named her one of their '30 under 30' in media.
She was also the author of Angels With Blue Faces, a non-fiction novella about a Northern Ireland cold case from The Troubles - the murder of Robert Bradford, the MP for South Belfast.
She had signed a two-book deal with Faber & Faber with her forthcoming book, The Lost Boys, which was due to be published in 2020.
"Shocking and tragic"
President Michael D Higgins said: "The people of Ireland will have heard with both shock, outrage and great sadness of the killing of the young journalist Lyra McKee in Derry last evening - a woman of talent and commitment, who was shot exercising her profession.
"Sabina and I send our deepest sympathies to her family and friends and to all those who knew her and worked with her."
Tánaiste Simon Coveney said: "The news from Derry is shocking and tragic.
"Our thoughts are with the family and friends of Lyra McKee today. I call on anyone with information to come forward to the PSNI.
"There is no justification for this tragic loss of life and I call on those intent on violence and disturbances to stop.
"As we mark the 21st anniversary of the Good Friday Agreement, we are reminded that the vast majority of people of this island voted overwhelmingly for peace and reconciliation and an end to violence.
"There can be no going back to those awful days."
Justice Minister Charlie Flanagan said: "I am utterly shocked by the killing last night of Lyra McKee. Such a reckless regard for human life is horrendous.
"My thoughts are with all the family and friends of Lyra and all those impacted by this dreadful killing.
"For a 29-year-old to be killed while simply doing their job is beyond words.
"We don't say it enough but journalists play a vital role in society, exposing themselves to danger so we can get a true insight into events.
"The courageous PSNI officers who risk their lives to maintain public safety deserve nothing less than wholehearted support from everyone in the community."
Politicians across the political spectrum in the North have widely condemned the killing.
Party leaders at Stormont have released a joint statement on her murder.
They said: "We want to express our condemnation in the strongest terms possible at the murder of journalist Lyra McKee.
"The murder of Lyra McKee is first and foremost a devastating loss for her grieving partner, family and friends, and our thoughts are with them at this awful time.
"Lyra's murder was also an attack on all the people of this community, an attack on the peace and democratic processes.
"It was a pointless and futile act to destroy the progress made over the last 20 years, which has the overwhelming support of people everywhere.
"We are united in rejecting those responsible for this heinous crime.
"They have no support in the community, must be brought to justice and should disband immediately.
"We reiterate our support for the PSNI, who while carrying out their duties were also the target of last night's attack. We call on anyone with any information to bring that forward to the police and assist their inquiries.
"This is a time for calm heads."
Earlier, Sinn Féin's deputy leader Michelle O'Neill condemned what she called a "senseless loss of life".
"I am shocked and saddened at the tragic news that a young woman has been shot dead by so-called dissidents in the Creggan estate tonight.
"My first thoughts and that of my party are with the family of the woman killed. This is a senseless loss of life.
"The murder of this young woman is a human tragedy for her family, but it is also an attack on all the people of this community, an attack on our peace process and an attack on the Good Friday Agreement.
"I unreservedly condemn those responsible for killing this young woman.
"We will remain resolute in our opposition to the pointless actions of these people who care nothing for the people of Derry.
"We remain united in our determination to building a better and peaceful future for all."
My heart goes out to the family of the young woman shot dead by so-called dissidents. This was an attack on the community, an attack on the peace process and an attack on the Good Friday Agreement. I appeal for calm and for anyone with information to bring it to the PSNI https://t.co/m8O43RkuRI
— Michelle O’Neill (@moneillsf) April 19, 2019
DUP leader Arlene Foster said it was "heartbreaking news."
"A senseless act. A family has been torn apart. Those who brought guns onto our streets in the 70s, 80s & 90s were wrong.
"It is equally wrong in 2019. No one wants to go back. My thoughts are also with the brave officers who stood in defence of their community", she tweeted.
Heartbreaking news. A senseless act. A family has been torn apart. Those who brought guns onto our streets in the 70s, 80s & 90s were wrong. It is equally wrong in 2019. No one wants to go back. My thoughts are also with the brave officers who stood in defence of their community. https://t.co/77JO3YSYOB
— Arlene Foster DBE PC #ProudofNI. (@ArleneFosterUK) April 19, 2019
While leader of the Ulster Unionist Party (UUP) Robin Swann said news of the death was "devastating".
He tweeted: "A precious life lost, we can't go back to this nor can we allow others to drag us back."
Devastating news coming out of Londonderry tonight, a precious life lost, we can't go back to this nor can we allow others to drag us back.
— Robin Swann : North Antrim UUP MLA (@RobinSwannMoH) April 18, 2019
The North's Policing Board said it was "utterly shocking that a young woman has been killed tonight in Derry/Londonderry."
They are appealing to anyone with information to contact police.
Tributes have also been paid to Ms McKee on social media:
Shocked by news that woman shot dead in Derry last night has been named locally as @NUJofficial Lyra McKee. We are shocked by killing of a journalist of courage, style and integrity. Sympathy to her partner, family and many friends. @kathrynjohnston
— Séamus Dooley (@Seamusdo) April 19, 2019
I can’t believe Lyra McKee was murdered last night. She was at a point in her life when she was so happy & excited about life ahead of her. I feel sick & so angry. Why would anyone do this? Such a senseless, needless, cruel act. My thoughts are with Sara & all of Lyra’s family.
— Nichola Mallon (@NicholaMallon) April 19, 2019
This is the lovely mind of the person murdered in Derry overnight. This is why Northern Ireland matters and why Northern Ireland will never be dragged backwards. #LyraMcKee
In Memory Of | Lyra McKee | TEDxStormontWomen https://t.co/BJVE67zOhT.
— Chris Donoghue (@chrisrdonoghue) April 19, 2019
A journalist has been killed covering riots in Derry. Her name was Lyra McKee. She was 29. She recently signed a two-book deal with Faber, who called her a "rising star of investigative journalism". This is her last tweet, sent from the scene of the unrest. pic.twitter.com/0gk1Fa7Du0
— Naomi O'Leary (@NaomiOhReally) April 19, 2019
We are shocked and anguished by reports that our brave and wonderful colleague Lyra McKee has been murdered amid violence in Derry, NI. She has edited Mediagazer since 2011. Our hearts go out to her family and friends.
— Gabe Rivera (@gaberivera) April 19, 2019
Lyra McKee, Mediagazer editor, freelance writer, and journalist who wrote about the legacy of Northern Ireland's Troubles, was killed amid violence in Derry, NI (The Irish News)https://t.co/nh310uDu8khttps://t.co/Y4VrqoV7Qm
— Mediagazer (@mediagazer) April 19, 2019
The National Union of Journalists (NUJ), of which Ms McKee was a member, has condemned the "indiscriminate killing".
Michelle Stanistreet, NUJ general-secretary, said: "The killing of a journalist in these circumstances is deeply shocking.
"To wake up to this news on Good Friday morning is disturbing and profoundly saddening.
"A young, vibrant life has been destroyed in a senseless act of violence.
"Our thoughts are with her partner, family and many friends and colleagues. A bright light has been quenched and that plunges all of us in to darkness."
Séamus Dooley, NUJ assistant general-secretary, said: "Lyra McKee was a journalist of courage, style and integrity. She was a woman of great commitment and passion.
"I have no doubt that it was that commitment which led to her presence on the streets of the Creggan last night, observing a riot situation in the city.
"She had tweeted just minutes before being hit by a bullet. She had also spoken to a journalist colleague from the riot scene."
"This killing serves as a reminder of the ongoing instability in Northern Ireland and must serve as a reminder to those in positions of political leadership to end the political deadlock.
"Our thoughts are also with the members of the PSNI, especially those who came to Lyra’s assistance after she had been struck by a bullet."
Additional reporting Michael Staines
Main image: Lyra McKee, courtesy of her family and her partner