RAFAH, May 18: Israeli forces killed 20 Palestinians on Tuesday in the biggest raid on the Gaza Strip for years as tanks and infantry thrust into a militant stronghold despite an international outcry.

The assault on the Rafah refugee camp, by one of the largest Israeli forces in action since the start of a Palestinian uprising in 2000, drew condemnation because of threats to destroy hundreds of Palestinian homes in the occupied territory. But the army said there were no plans for any systematic demolition during what it called an open-ended operation to stop the smuggling of weapons through tunnels from Egypt.

"When the fighting is over, most of the residents will almost certainly return to their homes," said Colonel Pinky Zuaretz, a field commander. Under cover of darkness, troops fanned out into Rafah's Tel al-Sultan neighbourhood, taking vantage points in bullet-pocked buildings as soldiers searched house-to-house for militants and fought Palestinian gunmen.

Israel had amassed more forces in Gaza than since capturing it in the 1967 Middle East war, commentators said, for a raid launched after militants killed 13 soldiers there last week and dealt the army its biggest blow for two years.

"We are afraid," said Miriam Abu Jazzar, surveying the blood-stained ruins of her daughter's home, smashed by a missile. "Every hour there is shooting." Helicopter gunships killed seven Palestinians, at least three of them gunmen. The identities of the others were unclear.

Palestinian witnesses said the four had gathered for dawn prayers at a mosque set ablaze by the missile strike. Israeli military officials said missiles hit a band of gunmen.

Six Palestinians, at least one of them a gunman, were killed in street fighting, medics said. About 20 people were wounded in the air attacks and street fighting of "Operation Rainbow".

FEARS OF MASS DEMOLITIONS: "We will die and they will die, but we are Muslims and we go to heaven. They will go to the fires of hell," said 30-year-old Palestinian policeman Ashraf al-Jamal.