Police in Northern Ireland say they have arrested an 18-year-old man in the case of a police officer killed by IRA dissidents.

Police say detectives investigating the murder of Constable Stephen Carroll made the arrest on Tuesday.

The Continuity IRA has claimed responsibility for killing the 48-year-old officer as he sat in his patrol car Monday night in the town of Craigavon. Just 48 hours earlier two British soldiers had been shot dead in an attack claimed by another IRA splinter group.

The attacks were the first killings of British security forces in Northern Ireland since 1998. That was the year that rival British Protestant and Irish Catholic politicians struck a peace deal designed to end decades of bloodshed.