A former British soldier has been arrested by detectives investigating the Bloody Sunday killings in Derry.

Sources say the man is a former member of the Parachute Regiment.

The 66-year-old was arrested in Co Antrim and is being held at a police station in Belfast, the Police Service of Northern Ireland confirmed.

He was detained by officers from the Legacy Investigation Branch.

Thirteen people died on January 30th 1972 in one of the worst incidents of the Troubles when soldiers fired on unarmed demonstrators in Co Derry.

Another victim died months later.

The officer leading the investigation, Detective Chief Inspector Ian Harrison, said the arrest marked a new phase in the overall investigation into the killings.

It is the first arrest since the murder inquiry into the events in Derry began in 2012.

The investigation was launched after a report found none of the victims was a threat to soldiers when they were shot.

British Prime Minister David Cameron called the army's actions "unjustified and unjustifiable" after the report's publication in 2010.

In September, police said they intended to interview seven former soldiers about their actions on Bloody Sunday.

Northern Ireland security correspondent, Alan Murray, told Newstalk Lunchtime some 100 others have already been contacted.