LONDONDERRY, Northern Ireland (Reuters) – Northern Ireland police have made two arrests in relation to Saturday’s car bomb in Londonderry and their main line of inquiry is that the New IRA militant group was responsible for the attack, officers said on Sunday.

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.

Assistant Chief Constable Mark 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.