Police Chief Insp.-Gen. Dudi Cohen on Friday said that Thursday's terror attack could not have been prevented even if there would have been a security guard at the entrance of the yeshiva. "The terrorist was very decisive and well prepared with a big arsenal of weapons - a real war machine. No security guard could have prevented the attack," Cohen said. During a press conference which he held Friday afternoon, Cohen said there was no reason to believe the event was the beginning of a third Intifada. Also on Friday, Hamas backtracked on their claim of responsibility for the deadly attack in Jerusalem. Ibrahim Daher, head of Hamas' al-Aqsa radio, said his station put out an earlier claim of responsibility prematurely, based on confused information. Abu Obeida, a spokesman for Hamas' military wing, confirmed the group was not taking credit for the attack - at least yet. "There may be a later announcement ... But we don't claim this honor yet," he said. Earlier, a Hamas radio presenter said the group's military wing had "promised a jolting response" to this week's violence in the Gaza Strip in which more than 120 Palestinians were killed by the Israeli military, many of them in the northern Gaza town Jebaliya. The radio referred to the Jerusalem attack as "the fruits of what happened in Jebaliya" and called on believers to "celebrate this victory against the brutal enemy." The announcement came as thousands of mourners marched in funeral processions for the dead students, a closure was imposed on the West Bank and an Israeli official indicated that fledgling peace talks with the Palestinians would go on despite the violence. Israel will push ahead with talks "so as not to punish moderate Palestinians for actions by people who are not just our enemies but theirs as well," the Israeli official said, speaking on condition of anonymity because the government had yet to make an official announcement. Meanwhilem, Israel Beiteinu Chairman Avigdor Lieberman on Friday blamed Thursday's terror attack in Jerusalem on Arab MKs in the Knesset. "Whoever calls on IDF operations in Gaza which are aimed to protect southern residents 'war crimes' cannot escape from responsibility for the terror attack." British Prime Minister Gordon Brown has condemned the Jerusalem attack, describing it as "an attempt to strike a blow at the very heart of the peace process". Mr Brown said he had sent his condolences to Prime Minster Ehud Olmert. Public Security Minister Avi Dichter on Friday called for the expulsion to the West Bank of Arabs in east Jerusalem who have been involved in terrorist activity. "We need to find a legal and legitimate way to kick those few Palestinian Arabs in east Jerusalem who make it their choice to aid and take part in terrorism back to Ramallah," Dichter told mourners, referring to the major West Bank city on the outskirts of Jerusalem.