In the biggest sweep in months, Israeli troops hunting for militants stormed dozens of homes in the West Bank city of Nablus on Wednesday, ordering residents to line up at dawn as tanks blocked roads and helicopters hovered above.
Yasser Arafat denounced the raid as a "new war crime that the Israeli forces are committing against our people, our cities and our villages."
The Nablus raid was triggered by a weekend shooting attack at Kibbutz Metzer, an Israeli communal farm. The attack by a gunman left five Israelis dead, including two small children -- brothers aged four and five years -- and their mother.
Hundreds of soldiers backed by about 100 armored vehicles and helicopter gunships poured into Nablus before dawn Wednesday.
It was the biggest sweep in the city since Israel's "Defensive Shield" offensive in April, and military commentators said they expected the operation to go on for many days.
Troops have been in Nablus for most of the past seven months, enforcing curfews and manning checkpoints.
The focus of Wednesday's raid were several alleged militant strongholds -- the Old City, two neighborhoods near An Najah University as well as the Balata and Askar refugee camps on the outskirts of Nablus.
There were sporadic gunfights but no injuries. Several explosions were heard in Nablus' Old City, or Casbah, apparently set off by soldiers breaking open doors.
Tanks sealed all exits from the Casbah, a maze of alleys and underground passages and the scene of fierce fighting in April. Troops took over a nearby girls' elementary school as a makeshift base.
Israel declared Nablus a closed military zone, and soldiers barred journalists from taking pictures or talking to those rounded up. The army said 30 suspected militants were arrested in the raid.