By Ian Graham BELFAST (Reuters) - A prison officer was killed in Northern Ireland on Thursday when he drove into a hail of bullets and crashed off a motorway at high speed, in an attack blamed by police and politicians on militant nationalists. David Black, who was a member of the protestant Orange Order, worked at the top security Maghaberry Jail where militant nationalists are protesting against their living conditions. Black, a 52-year-old father of two approaching retirement after more than 30 years of service, was shot by a gunman in a car which pulled alongside his and was later found burned out, Northern Ireland's Chief Constable told a news conference. "It demonstrates the recklessness and ruthlessness and sheer dangerousness of those who oppose peace and are dedicated to taking us back to those dark days of the past," police chief Matt Baggott said. Northern Ireland's justice minister acknowledged that prison officers had recently been targeted by militant nationalists, forcing some to move house. It has not been disclosed if Black was one of those. Finlay Spratt, the chairman of the Prison Officers Association, criticized the authorities for dropping security around off-duty officers since the end of the bloody campaign known as "The Troubles" 14 years ago. More than 3,600 people were killed in the British-controlled province when Catholic nationalists seeking union with Ireland fought British security forces and mainly Protestant Loyalists determined to remain part of the United Kingdom. Militant nationalists have stepped up attacks in recent years. Two soldiers and a policeman were shot dead in March 2009 and another policeman was killed by a car bomb in April 2010. British Prime Minister David Cameron said: "These killers will not succeed in denying the people of Northern Ireland the peaceful, shared future they so desperately want." Reporting by Ian Graham; Writing by Padraic Halpin; Editing by Stephen Powell