By Nidal al-Mughrabi BEIT HANOUN, Gaza, Nov 9 (Reuters) - Palestinian militants vowed revenge after an Israeli artillery barrage killed 18 civilians in the Gaza Strip in the deadliest military strike in four years, prompting the Jewish state to declare a high alert. Wednesday's carnage in the town of Beit Hanoun rallied Palestinians after months of factional infighting. A wave of censure in Europe and the Middle East brought new scrutiny on Israel's fighting tactics in a territory it quit last year. Israeli leaders voiced remorse for the killings, which army officers said were probably caused by shells that overshot after being aimed at areas used by Palestinian militants to fire rockets. The dead included 13 members of one extended family. Thousands of Palestinians were expected to attend their funerals in Beit Hanoun on Thursday. Israeli Defence Minister Amir Peretz ordered a halt to artillery fire in Gaza and for a probe to completed by Thursday. But Khaled Meshaal, leader of the governing Palestinian Islamist militant group Hamas, urged retaliation. Hamas declared a partial truce in March 2005, which expired at year's end. It has not carried out a suicide bombing in Israel since 2004. "All Palestinian groups are urged to activate resistance despite the difficult situation on the ground. Our confidence in our military wing to respond is great," said Meshaal, who is based in Damascus. Hamas's armed wing, decrying Washington's "political and financial support" for Israel, appeared to call on Muslims to attack U.S. targets, urging them "to teach the American enemy harsh lessons". Two other militant groups spearheading a 6-year-old revolt, Islamic Jihad and al-Aqsa Martyrs Brigades, also vowed revenge. While the European Union said it was "appalled" by the Gaza shelling, an initial response by the United States stopped short of reprimanding Israel, whose prime minister, Ehud Olmert, is due to meet President George W. Bush in Washington on Monday. Israeli police declared a high security alert, but the army said there would be no let-up in operations against militants. "What happened in Beit Hanoun is very grave," Major-General Yoav Galant, chief of Israeli forces around Gaza, said in a television interview. "But I think that there is no weapon, given it is used properly, that should not be used in order to protect Israeli civilians and soldiers." The Beit Hanoun shelling brought together Palestinian Prime Minister Ismail Haniyeh of Hamas and moderate President Mahmoud Abbas, who have been at odds over a proposal to create a unity government that might help lift a Western aid blockade. Hamas has balked at Abbas's demands that it recognise Israel and renounce violence, terms set by foreign power-brokers. Haniyeh suspended coalition talks after the Beit Hanoun shelling, but said he expected them to resume within days. A senior Abbas aide said a unity government could be imminent.
