A third man was arrested in Northern Ireland on Tuesday over the attempted murder of a police officer who found a bomb underneath his car.

A 41-year-old man was detained in west Belfast, police said, after two men aged 34 and 25 were arrested Monday in the Belfast area.

The targeted officer found the viable device underneath his vehicle in Belfast on Sunday. Army bomb disposal experts carried out a controlled explosion.

Senior officers have said the attack could have killed the off-duty policeman and his family.

A dissident republican group calling itself the "New IRA" (Irish Republican Army) claimed responsibility for the attack.

Dissident republicans want Northern Ireland to leave the United Kingdom and join the Republic of Ireland to the south, but have not given up violence as a means of achieving their aims.

The IRA declared a formal end to its armed campaign in 2005, saying that it would pursue its aims through peaceful means.

Its political wing Sinn Fein is now part of the power-sharing government in Belfast, formed of Catholic and Protestant parties.

Around 3,500 people died in Northern Ireland's three decades of violence between Protestants, favouring continued union with Britain, and Catholics seeking a unified Ireland.

A 1998 peace agreement largely ended the conflict, but sporadic unrest and bomb threats continue as dissident offshoots remain violently opposed to those accords.