Forces increased security along the northern border with Lebanon in fear of a Hezbollah attack. The Lebanese guerrilla group fired anti-tank missiles and artillery rounds at Israeli troops late Monday, drawing Israeli return fire. No casualties were reported.

Outside the country, Israel stepped up security at embassies, consulates and other official offices. Israeli officials also advised various Jewish centers around the world to take precautions. Israel fears that groups operating abroad, like Hezbollah or al-Qaida, might strike to show solidarity with Hamas, the officials said.

The assassination, which killed seven other people, received large support in Israel, despite the belief that it will spark more violence. The Yediot Ahronot daily published a poll showing 60 percent of Israelis that killing Yassin was the right thing to do, while 32 percent thought it was wrong.

On the other hand, 81 percent of Israelis believe the assassination will lead to an increase in militant attacks, according to the Dahaf.

"No one in the system, not even Sharon, believes that the assassination of the sheik will reduce the scope of terror. There is no strategy here: just bitter frustration and mounting difficulty to look the voters in the eye," wrote Yediot columnist Nahum Barnea.

The attack drew widespread condemnation from Arab and European governments. The United States, Israel's closest ally, said it was "deeply troubled" by the assassination and urged restraint.

The killing was part of Prime Minister Ariel Sharon's effort to crush Hamas ahead of a possible Israeli withdrawal from Gaza. However, the killing was seen as a huge gamble that could galvanize the Palestinians behind Israel's arch-foe Hamas.

The missile strike dealt also what could be the final blow to the stalled U.S.-led "road map" peace plan. It also angered Egypt and Jordan, two moderate Arab states whose tacit support Sharon needs for any unilateral withdrawal from Gaza.

A team of top Israeli officials, including Sharon's bureau chief Dov Weisglass and National Security chief Giora Eiland, were headed to Washington on Tuesday to discuss the withdrawal plan with American officials.