Police in Northern Ireland have arrested two men in their twenties following a suspected car bomb attack in Londonderry.
CCTV images captured the moment a suspected bomber parked outside the courthouse in Derry and someone can be seen running from the vehicle.
A group of young people walk by and moments later there is an explosion.
Nobody was killed.
Police say two men were detained hours after the explosion.
Investigators say they are looking into whether the militant group calling itself the New IRA was responsible for Saturday's blast.
Assistant Chief Constable, Mark Hamilton, told reporters the risk of further violence remains high.
"Unfortunately the threat has been at the 'severe' level for nearly 10 years now so I don't necessarily see this as an escalation in anybody's capability," he said.
"I just see it as a continuance of the hatred that the dissident republicans in particular have for this city and the people in it. It is worrying, of course it's worrying."
Londonderry, also known as Derry, has a long history of sectarian tension and violence.
The group suspected of carrying out this attack are opposed to the 1998 peace deal which ended three decades of violence in the British-run province.
The bomb which went off has been described as a "crude device" but the Police Service of Northern Ireland said the incident was "unbelievably reckless".