Detectives investigating the attempted murder of a police officer in Northern Ireland have made three arrests.
Two men, aged 25 and 34, were detained in Belfast on Monday night after the off-duty constable discovered a bomb under his car at his home in the city on Sunday. The third man, a 41-year-old, was arrested on Tuesday.
Senior officers say the device could have killed the officer's wife and two young children. Police Service of Northern Ireland assistant chief constable George Hamilton said: "If that officer had not checked under his car we would have been looking at a murder or multiple murders."
Police are on high alert after the attempted murder and the separate discovery of a pipe bomb near the police station at Tandragee in Mid Ulster.
The booby-trap device in Belfast was defused in a controlled explosion by the army. It was recovered partially intact and police hope forensic tests will identify those who made and planted it.
Hamilton said he was linking the attack to dissident republicans. Police have been warning for months that republican militants remain determined to kill members of the security forces.
On 1 November, prison officer David Black was shot dead as he drove along the M1 to his work at the high-security Maghaberry prison in County Antrim, which houses dissidents. A group styling itself the "new IRA" claimed responsibility for that attack. It was formed in the summer from several splinter groups.
Less than two weeks later, an under-car booby-trap bomb was found lying on a road in west Belfast. It is believed to have fallen from a soldier's car.
In recent months police in Belfast and Derry have recovered mortars capable of piercing the armour of police vehicles and causing multiple deaths. During the past year, police have arrested 115 people suspected of dissident republican activity, and 35 have been charged. Sixty-four officers have been forced to leave their homes during the past five years because of intelligence that they were being targeted for potential attack.
Many others have had additional security measures such as bulletproof glass installed in their homes.
The chairman of Northern Ireland's Police Federation said he would be seeking a meeting with the PSNI chief constable, Matt Baggott, to discuss officers' personal security and the recruitment of extra staff.
Terry Spence said more needed to be done to ensure officers' safety at home and at work.