Evening top 5: "Active shooter" at YouTube HQ; Major gun seizure in Dublin; Teachers threaten coordinated strike action

The top stories of the day on Newstalk.com

Police responding to "active shooter" at YouTube headquarters

Police are “responding to an active shooter” at YouTube's headquarters in California.

San Bruno Police have urged the public to "stay out of the area."

Images posted on social media showed people being lead with their hands up outside YouTube's office.

A witness at the scene said a SWAT team had arrived and armed police had surrounding the building.

San Francisco General Hospital has confirmed it has received an unknown number of victims from the incident.

Gardaí uncover sub-machine gun and four handguns in Dublin

Gardaí have found a sub-machine gun and four handguns in a discarded backpack in Dublin this afternoon.

The discovery was made after officers chased a suspect in his 20s who was stopped during a routine operation in Coolock.

The arms were found after the suspect fled the vehicle he was driving and discarded the backpack.

The vehicle, believed to be linked to the investigation, has been seized by gardaí and the firearms will be forensically examined.

Teacher unions band together to threaten major strike action over pay

The Minister for Education has said it will be difficult to meet the early May deadline laid down by teachers to come up with concrete proposals on the restoration of pay.

70,000 teachers could go on strike this September if significant progress is not made on the issue by next month.

This afternoon all three of Ireland’s main teacher unions unanimously passed an emergency motion calling for coordinated strike action if the Government doesn't come up with a timeline to restore pay.

Over 20,000 teachers hired after 2011 are currently on a lower pay-scale than their colleagues hired before the cut-off.

UK chemical research experts unable to say where Salisbury nerve agent originated

Russian leader Vladimir Putin has called for an inquiry into the Salisbury attack after the United Kingdom’s chemical weapons research facility admitted it is unable to say where the nerve agent used in the attack came from.

This afternoon Gary Aitkenhead chief executive of the UK Defence Science and Technology Laboratory (DSTL) at Porton Down in Wiltshire said scientists were only able to confirm the substance involved was novichok – a military-grade nerve agent developed by Russia from the 1970s onward.

He said scientists cannot prove the agent used in Salisbury was made in Russia.

Britain has insisted the Russian state was behind the attack - with Russian diplomats expelled from Ireland, the UK, US, Canada, Australia and countries across Europe in response.

Data Protection Commissioner to investigate alleged data breach at INM

The Data Protection Commissioner is planning an investigation into an alleged data breach at Independent News and Media.

The Commissioner's office has confirmed that it was notified about the alleged breach last week.

It is suspected the emails of a number of staff including journalists were hacked.

This evening, Graham Doyle head of communications at the Data Protection Commissioner's Office said the investigation would focus on whether any personal data was accessed.