A British army major and two Ulster policemen were killed by a land mine in the bloodiest guerrilla action in Northern Ireland in a year, police said. The mine, operated by remote control, was detonated as a joint military and police patrol was passing a bridge in County Armagh about three miles from the Irish border. The three men were killed instantly, but no other patrol members were injured, police said. The dead soldi170197823135. The policemen were not named. The South Armagh Battalion of the outlawed Irish Republican Army claimed responsibility for the blast in a brief statement distributed to reporters in Belfast.