JERUSALEM?Palestinian police arrested a top Islamic Jihad activist in the West Bank town of Jenin on Wednesday, setting off a violent protest against Yasser Arafat’s security force.

The arrest came as Secretary of State Colin Powell scheduled a key Middle East policy speech for next week. An Israeli peace campaigner and a Palestinian spokeswoman said the United States no longer backs Israel’s demand for seven days of complete calm before peace talks resume.

Islamic Jihad leaders said Palestinian police pulled Mahmoud Tawalbi off a Jenin street and jailed him in Nablus, 15 miles to the south. Tawalbi, 23, was suspected by Israel of recruiting suicide bombers and sending them into Israel.

About 3,000 Palestinians protesting the arrest surrounded Palestinian Preventive Security headquarters in Jenin, firing guns, throwing grenades and burning cars.