The operation, which began Monday morning, was the largest military incursion into the Jenin refugee camp in recent years. It was the first major operation since the Israeli government declared its intention to unilaterally withdraw from the Gaza Strip this summer. The Israeli army said it had targeted militants in the camp that were planning suicide bombings or other attacks against Israeli civilians.

It said it was also searching for weapons and explosives. Hundreds of Israeli troops entered the camp and declared it a closed military zone. Helicopters fired missiles at suspected militant hideouts while tanks pounded homes and other buildings. Palestinians in the camp reported that some buildings were destroyed while others were damaged.

Israeli Prime Minister Ariel Sharon said the operation was a "vital" step in ensuring the security of the country. But Palestinian Prime Minister Ahmed Qurei condemned the operation as a "dangerous escalation" and called for an immediate withdrawal of Israeli forces. The United Nations, European Union and other international organizations also called for an immediate end to the operation and expressed concern over the number of civilian casualties.

The fighting in Jenin came as the Israeli government continued to prepare for its planned withdrawal from the Gaza Strip. The withdrawal, which is expected to take several months to complete, is seen by many as a way to ease tensions in the region and set the stage for future peace talks.