Bomb suspects under arrest in Northern Ireland

Police in Northern Ireland said four arrested in connection with Saturday night's car bomb in Derry city remained in custody on Monday morning.

Two men in their 20s were arrested in the early hours of Sunday, while another two, aged 34 and 42 were later detained in the city.

The car bomb exploded outside Bishop Street courthouse at around 8:10 pm while the area was still being evacuated. Police said they were given only 10-minutes warning before the explosion.

Dramatic CCTV footage of the incident released by police has revealed how a group of people had walked past the car containing the bomb just minutes before the explosion.

The bomb, which had been planted in a hijacked delivery van, caused no casualties or major damage. But after receiving a warning, the police had little time to evacuate children from a youth club nearby and hundreds of people from a luxury hotel and a masonic hall.

Police said their main line of inquiry is that the New IRA militant group was responsible for the attack.

Assistant chief constable Mark Hamilton described the bomb as a "crude device" and the attack as "unbelievably reckless".

"Clearly, it was a very significant attempt to kill people here in this community.

"Thankfully, the local community and the police service acted bravely together and we got everybody away just in time.

"But the bomb detonated just as we were leaving the area.

"The new IRA, like most dissident republican groups in Northern Ireland, are small, largely unrepresentative and determined to drive people back to somewhere they do not want to be."

Hamilton said dissident republican groups "always aspire to do bigger things", adding that the device "has not been as effective as they would have wanted for it to be".

"They have not killed anybody and they haven't caused widespread damage," he said.

The explosion followed a pattern of attacks in the city attributed to republican groups opposed to the peace agreement that ended the "Troubles" in Northern Ireland 20 years ago.

The Irish nationalist New IRA is one of a small number of militant groups opposed to a 1998 peace deal that largely ended three decades of violence in the British-run province. They have carried out sporadic attacks in recent years.

Hamilton said he did not see the bombing as an escalation of militant groups' capabilities but a continuation of a threat that has been officially at the "severe" level for 10 years.

Politicians across the United Kingdom and Republic of Ireland have condemned the attack.