HEBRON, West Bank (Reuters) - Israeli troops fired rubber bullets on Wednesday at Palestinian stone-throwers protesting at the killing of three Arab labourers by Israeli soldiers, witnesses said. The violence erupted while Israel's West Bank commander briefed his Palestinian counterparts on the findings of an Israeli investigation into the shooting deaths of the three at a checkpoint on Tuesday night. Witnesses said the protesters stoned troops and burned tyres at the entrance to Dura, the village near Hebron where the funerals were due to take place at 3 p. m. (1300 GMT). President Yasser Arafat's Palestinian Authority denounced the killings as a "massacre in cold blood". Israeli Prime Minister Benjamin Netanyahu telephoned Arafat late on Tuesday to express his condolences. In Hebron all shops and businesses shut down as part of a general strike called by Arafat's Fatah faction. It was unclear what Israeli Major-General Uzi Dayan, the commander of the West Bank, would tell the head of Palestinian forces in Hebron, Abdel Fatah Jaeidi, in talks attended by senior officials from both sides in Hebron. The two sides disputed the circumstances of the killings. The Israeli army said the Palestinians veered their truck into soldiers manning the checkpoint, wounding one. Soldiers opened fire. The army detained two soldiers for questioning and appointed a committee to probe the incident. Palestinian witnesses denied the car had tried to run over troops and said one soldier had opened fire after another had already waved the car through the checkpoint. Shortly after the shooting, scores of angry Palestinians took to Hebron's streets to hurl stones, bottles and firebombs at Israeli troops, who responded with rubber bullets, wounding more than 20 Palestinians. Palestinian Authority cabinet secretary Ahmed Abdel Rahman suggested in a sharply worded reaction to the killings that the Israeli government was indirectly responsible. The Israeli army appealed to Palestinian police to prevent violence.