In ordering the offices of militant Hamas and Islamic JIihad shut, Yasser Arafat has taken a step he has long resisted.

The two groups have claimed responsibility for dozens of bombing attacks against Israelis, including suicide bombings that have killed dozens, wounded hundreds and horrified Israel.

Arafat has hesitated to crack down on the Islamic groups, fearing civil war. However, under Israeli and U.S. pressure, he has begun arresting activists, driving leaders underground.

Israel, however, says the arrests are for show, and the main planners of the bombing attacks are still at large.

Arafat ordered the offices of the two groups shut Wednesday after attacks against Israeli settlers killed 10 and wounded 30.

Hamas said it was responsible for Wednesday's late-night bus attack, which caused the carnage in the West Bank. It was also thought to be involved in two suicide bombings in the Gaza Strip. Only the bombers died.

"The Palestinian leadership has decided to close all offices, centers and organizations and anything connected with Hamas and Islamic Jihad in the Palestinian territories," a Palestinian Authority statement said.

But the statement stopped short of declaring the two groups illegal or dismantling their military wings, as Israel and the United States have been demanding.

In closing all Hamas organizations, Arafat is hitting at a key function of the Islamic group: providing charity and welfare to Palestinians impoverished by 15 months of conflict, while the Palestinian Authority is near bankruptcy.

After Wednesday's attacks, U.S. envoy Anthony Zinni said Arafat "must move immediately to arrest those responsible for these attacks and to destroy the infrastructure of the terror organizations that support them."