The IDF wrapped up a four-day operation in Nablus on Saturday during which troops uncovered a Kassam manufacturing lab, several weapons caches and an underground tunnel system used by terrorists to hide and plan attacks against Israel. More than 20 terror suspects were arrested during the Nablus operation (19 belonged to Fatah's Aksa Martyrs Brigades), including 10 whom IDF sources said were involved in shooting attacks and placing bombs along roads in the area. A ready-for-use suicide explosive belt was also discovered. The army also arrested two officers of the Palestinian Authority's Military Intelligence Force for allegedly helping the Aksa Martyrs Brigades in Nablus, according to Palestinian sources. Hundreds of soldiers from the Paratroopers Brigade's Reconnaissance Unit, as well as the Haruv Battalion and elite Engineering Corps units participated in the operation, during which the military imposed a curfew on the city's casba, or marketplace, confining some 30,000 people to their homes. Despite being one of the IDF's largest operations in the West Bank in recent months, no one was killed during the clashes that erupted between soldiers and demonstrating Palestinian civilians. Palestinian medical officials said more than 40 residents were treated in local hospitals. On Thursday night, troops discovered a rocket-manufacturing lab inside a room beneath a building in the casba. Soldiers also found rails that were intended to be used as the rockets' launchers. Sources in the Central Command said the so-called rockets were not yet operational but underlined the necessity for continuous operations deep inside West Bank towns. The sources said the IDF worked closely with the Shin Bet (Israel Security Agency) throughout the operation. On Friday, PA Prime Minister Salaam Fayad accused Israel of compromising nascent Israeli-Palestinian peacemaking with the Nablus raid. In a radio interview Saturday, Fayad said he had called off a trip to Egypt to meet with Arab foreign ministers to attend to the developing situation in Nablus. "The current Israeli operation aims to heat up the atmosphere before [US President George W.] Bush's visit," he told an-Najah Radio. "They are trying to sabotage the Palestinian Authority's successes in the city." An official in Jerusalem rejected Fayad's criticism, saying that Israel was acting in the West Bank because the PA was not up to the challenge. "In the absence of effective action by the PA security forces, a vacuum will be created - a vacuum that will be exploited by the extremists. When the Palestinian security services are ready and capable of taking action, Israel will be ready to stand down," the official said. Before troops pulled out, Massoud Kalboneh, a 35-year-old construction worker, accused soldiers of roughing up his five-year-old nephew after he dived under a bed, unaware that he was a child and thinking he was trying to escape them. Because food wasn't able to get in, Kalboneh said he and his family had lived off stored cheese and olives, and baked their own bread. "This was one of the most aggressive raids" Nablus has known, he said. Mark Weiss and AP contributed to this report.