DUBLIN (REUTER) - The IRA once put up a sign in south Armagh, it said "Caution. Sniper at work." The killing of a British soldier on Wednesday night has raised fears the sniper is at work once again. The bullet which slew 23-year-old Lance Bombardier Stephen Restorick was fired by a high-velocity rifle, probably from some distance and with fatal accuracy. The woman the soldier was talking to at the time told reporters tearfully on Wednesday night that all she heard was a "crack". The soldier slumped as he was handing her back her driving licence at an army checkpoint. Security spokesmen declined to comment on the weapon used in the killing, which brought Northern Ireland back to the brink of renewed sectarian war between the IRA, which seeks to end British rule, and Protestant Loyalists who want to maintain it. The soldier was shot at a permanent checkpoint outside the village where he was checking the papers of drivers. Eyewtnesses said soldiers who arrived on the scene were visibly shocked. Security sources say that the fear of being in a sniper's sights is part of the IRA's constant psychological warfare against 18,000 British troops in the province which has a long history. A huge bomb was left in a residential area if a town on February 9, the first anniversary of an IRA bomb attack at London's Canary Wharf business complex which marked the end of the guerrillas' ceasefire. Police said the device could have killed many people and caused huge damage had it been detonated. The IRA says its political wing, Sinn Fein, should be invited to Belfast peace talks but Britain says only an unequivocal and permanent truce will give it a place at the talks. Irish peace broker John Hume said that Britain had agreed to meet relatives of 13 people killed by British troops on "Bloody Sunday" 25 years ago to hear new evidence about the killings. Britain's Northern Ireland Secretary, Sir Patrick Mayhew, was to meet the families. British troops fired into a civil rights demonstration in Londonderry, Northern Ireland, in January, 1972, killing 13 people and wounding several more. An official investigation exonerated the soldiers, who said they believed they were coming under fire from IRA guerrillas. But a new book and legal study suggest that a sniper or snipers fired on the crowd form the walls of Londonderry's ancient city, contradicting official evidence that only soldiers on the ground took part in the shooting. Another study says that testimony the British soldiers gave to police was not presented to the official investigation which was led by the then Chief Justice, Lord Widgery. Hume said he was confident a new evidence would prompt a new investigation. British Prime Minister John Major vowed he would not give in to terrorism. Gerry Adams, President of the IRA's political wing, Sinn Fein, said in a brief statement the shooting was "a tragic event which re-emphasises the need for for all of us to redouble our efforts to rebuild the peace process." Adams's words were directed at Major's refusal to talk to Sinn Fein. British and Irish officials accused him of hypocrisy by expressing regret for an action they blamed on his IRA supporters, who share Sinn Fein's goal of ending British rule. Pro-British politicians fear that the IRA is hoping to create mayhem so that whichever government takes over after the British election is forced to invite Sinn Fein to negotiations without conditions. Ken Maginnis, security spokesman for the mainstream Ulster Unionist Party, which wants the province to remain British, said the killing was an IRA ploy to force Loyalist retaliation. Loyalist guerrillas killed hundreds of members of the Catholic community, from which the IRA draws support, to avenge attacks by the IRA in a 28-year war which killed 3,200.