Four men have been arrested in Londonderry in connection with a car bomb in the city on Saturday.

Police said the "unbelievably reckless" attack may have been carried out by dissident republican group the New IRA.

The attack came shortly after 8pm on Saturday when a vehicle exploded on Bishop Street.

The Police Service of Northern Ireland (PSNI) said the bomb was a "crude device".

Police near the scene of a suspected car bomb on Bishop Street in LondonderryPolice near the scene of a suspected car bomb on Bishop Street in Londonderry (Steven McAuley/PA Wire)

Two men, in their 20s were arrested earlier in the day on Sunday, before a further two men, aged 34 and 42, were arrested later on Sunday evening.

No-one was injured in the attack which has been condemned by politicians across Northern Ireland’s divide.

The PSNI’s Assistant Chief Constable Mark Hamilton said hundreds of people, including hotel guests and children from a church youth club were evacuated from the area.

“At around 7.55pm last night officers on patrol in Bishop Street spotted a suspicious vehicle and were making checks when, around five minutes later, information was received that a device had been left at the courthouse,” he said.

The scene of the explosionNo-one was injured in the attack (PSNI)

“We moved immediately to begin evacuating people from nearby buildings including hundreds of hotel guests, 150 people from the Masonic Hall and a large number of children from a church youth club.

“The device detonated at 8.10pm.”

Mr Hamilton said police believe the vehicle used in the attack had been hijacked from a delivery driver in the Quarry Street a short time before the explosion.

He condemned the attack as “unbelievably reckless”.

“Thankfully the attackers failed to kill or injure any members the local community out socialising and enjoying the best of what the city has to offer,” he said.

“The people responsible for this attack have shown no regard for the community or local businesses. They care little about the damage to the area and the disruption they have caused.”

A number of church services in the area have been cancelled due to the ongoing security operation.

The Mayor of Derry John Boyle has challenged those responsible to explain themselves.

Londonderry explosionJohn Boyle condemned the attack (Steven McAuley/PA Wire)

“I would actually like to ask the people responsible for this what it actually was that they thought they were going to achieve. It achieves nothing, it didn’t achieve anything in the past, it didn’t achieve anything right now,” the SDLP mayor said.

“This is the past and it has to stay in the past. We don’t want to see any more of it.”