The IDF began a gradual withdrawal from the terrorist stronghold of Nablus late Monday night following two days of intensive operations. Operation 'Hot Winter' - launched Sunday to prevent Palestinian terrorist attacks - was not completely over and there were plans to return to the city in the coming days, IDF sources said. "The operation has proven itself," an officer said, referring to the discovery of four explosives labs and the apprehension of terrorist suspects. "We are not done and the operation will continue." On Monday, the IDF stepped up its operations in Nablus as soldiers blocked off streets in the densely-populated casbah and tens of thousands of residents remained confined to their homes under a military curfew. One Palestinian was killed Monday. Central Command sources said the Palestinian was killed after Nahal Brigade troops fired at armed Palestinians on a roof inside the casbah. According to Palestinian medics, Anan al-Teibi, 42, was shot in the neck while he was in his home in the old city. Teibi's son was wounded and hospitalized, the medics said. Palestinian Authority Prime Minister Ismail Haniyeh condemned "the criminal Israeli assault on Nablus," saying it was designed to undermine Palestinian efforts to form a unity government. PA negotiator Saeb Erekat said the offensive would "undermine the efforts that are being made to sustain the cease-fire with Israel." Troops from the Haruv Battalion discovered two explosives labs, filled with pipe bombs, gas balloons, explosives, computers and electrical wires. On Sunday, troops discovered two explosives labs in the city, dubbed the West Bank's "terror capital" by the IDF. Soldiers also discovered what the IDF called a "terror studio," which was used by terrorist groups to film suicide bombers' last remarks before being dispatched to their targets. In 2006, more than 100 suicide bombers from Nablus were caught by the IDF on their way to attacks. On Sunday, troops broke into transmissions of local TV and radio stations and called for the surrender of seven wanted terrorists. The fugitives were high-ranking operatives affiliated with Islamic Jihad, Tanzim and the Aksa Martyrs Brigades. PA security officials said 30 people have been detained since the raid began Sunday, not including the seven fugitives. The sweep was Israel's largest in the West Bank since last July.