Islamic militants are not making it easy for Yasser Arafat. Their leaders have gone underground, urging fellow fugitives not to turn themselves in to Palestinian police, and vowed more attacks.
Arafat is under intense U.S. and Israeli pressure to jail militants, but confronting them also means taking on Palestinian public opinion and risking Palestinian unity.
When Palestinian police went to the Gaza City home of Hamas spiritual leader Sheikh Ahmed Yassin to place him under house arrest on Thursday, Hamas gunmen shot at them. Officers returned fire, killing 21-year-old Hamas supporter Mohammed Silmi, security officials said.
Other activists set fire to a police jeep and threw stones at policemen. For hours, police outside the house fought sporadic battles with more than 1,500 Hamas supporters.
Hamas has opened fire before on Palestinian security forces, who are largely recruited from Arafat's Fatah movement, but such gunfights are rare.
"We came on to the street to reflect our anger against the Palestinian Authority's procedures against Sheikh Yassin," said 22-year-old student Izzadine Abu Ghaya, one of the protesters outside the house of the cleric, who is a quadriplegic.
"We in Hamas are not going to accept the Palestinian Authority's arrest campaign," the tall, bearded young man said. "We will not keep silent."
Abdel Aziz Rantisi, a Hamas leader who went underground at the start of the crackdown, posted a message on a Web site telling fellow fugitives not to give in to American pressure.
Another Hamas leader in Nablus, Adnan Asfor, said the militants were refusing to turn themselves in because "no one can guarantee their safety in the prison," and there were fears the prison might be targeted by Israeli forces.
In open defiance of Arafat's proclamation of a cease-fire, militant Islamic groups have kept up their bombing campaign against Israeli civilians.
Hamas claimed responsibility for blasts in Jerusalem and Haifa last weekend, which killed 25 people along with three suicide bombers.
Islamic Jihad said it sent the suicide bomber who blew himself to pieces outside a Jerusalem hotel on Wednesday, lightly injuring two bystanders. It said the attack was only the start of a new wave of bombings.
The weekend killings, which came while Israeli Prime Minister Ariel Sharon was visiting the United States, brought Israeli and American demands that Arafat take swift and decisive action against the militants.
Palestinian security officials said 180 Islamic militants have been rounded up since the arrest sweep began Sunday. However, Israeli officials said the leaders of the militant groups were still at large.
In the West Bank on Thursday, police raided the homes of suspected Hamas activists in four towns -- Qalqilya, Tulkarem, Nablus and Jenin -- only to find all but one of them had fled.
In Nablus, the family of fugitive Mohannat al-Taher cursed the Palestinian Authority and said the Palestinian security agents who ransacked his house behaved worse than the Israeli army when it occupied the city.
"What happened to them? They lost their minds," said al-Taher's mother Ummaya, bemoaning the breakdown of Palestinian unity.
"Yesterday they were working together," she said.