Hamas militiamen have rounded up hundreds of Fatah activists on suspicion of "collaboration" with Israel during Operation Cast Lead, Fatah members in the Gaza Strip told The Jerusalem Post on Monday.

They said the Hamas crackdown on Fatah intensified after the cease-fire went into effect early Sunday morning.

The Fatah members and eyewitnesses said the detainees were being held in school buildings and hospitals that Hamas had turned into make-shift interrogation centers.

Hamas has also renewed house arrest orders that were issued against thousands of Fatah officials and activists in the Gaza Strip shortly after the military operation started.

A Fatah official in Ramallah told the Post that at least 100 of his men had been killed or wounded as a result of the massive Hamas crackdown. Some had been brutally tortured, he added.

The official said that the perpetrators belonged to Hamas's armed wing, Izaddin Kassam, and to the movement's Internal Security Force.

According to the official, at least three of the detainees had their eyes put out by their interrogators, who accused them of providing Israel with wartime information about the location of Hamas militiamen and officials...