Israeli tanks and helicopters fired on protesters in a refugee camp on Wednesday, killing 10 Palestinians and raising a two-day death toll to 33 in Israel’s bloodiest Gaza raid in years, witnesses said.Medics said more than 50 people were wounded in the besieged Rafah camp in the southern Gaza Strip and that the casualties included children and teenagers dismembered by the blasts.The barrage of Israeli fire sent a marching crowd fleeing in terror, some dragging bloodied comrades and others carrying wounded children.Expressing ‘‘deep sorrow over the loss of civilian lives’’, the Army said it did not fire deliberately at the procession but that tank fire designed to drive back the protesters may have caused casualties. It said gunmen were among the crowd.In a gently worded rebuke, US President George W. Bush said: ‘‘I urge restraint. It is essential that people respect innocent life to achieve peace.’’Palestinian President Yasser Arafat called the strike a ‘‘war crime’’ against peaceful demonstrators, demanded punishment for those responsible and appealed for international intervention. The firing began as marchers surged toward the Tel Sultan neighbourhood, focal point of Israel’s sweep into Rafah, to demand that humanitarian aid be allowed in. — (Reuters)