Israel launched a new crackdown on Hamas Thursday, rounding up top leaders in the West Bank after the failure of efforts to secure the release of a soldier. Security forces seized 12 senior Hamas leaders in pre-dawn raids in the occupied West Bank, including four members of the Palestinian Legislative Council, Hamas and the army said. Hamas denounced the action as “blackmail” following the collapse of Egyptian-brokered efforts to reach an agreement on an Israel-Hamas prisoner swap. The Palestinian Authority, headed by Fatah, also slammed the arrests and called on the international community to intervene. “These men have been the leaders of the ongoing effort to restore the administrative branch of the Hamas terror organization in the region, while attempting to strengthen the power and influence of Hamas,” an Israeli military spokeswoman said. Thirty-six Hamas MPs have been in jail since a major crackdown in the West Bank that followed the capture of Israeli soldier Gilad Shalit in June 2006. Among those arrested were Nasseredin Al-Shaer, who was deputy premier in the short-lived Hamas government formed in March 2006, and two senior Hamas officials in the West Bank, Raafat Nassif and Adnan Asfur, the group said. Palestinian Prime Minister Salam Fayyad condemned the arrests and called on the international community to intervene “to pressure Israel to immediately free all members of Palestinian parliament whom they are holding.” A spokesman for President Mahmoud Abbas blasted the arrests as “kidnappings” aimed at torpedoing reconciliation talks under way between Fatah and Hamas in Cairo. The arrests follow the failure this week of the Egyptian-mediated negotiations for a prisoner swap that would entail the release of Shalit in exchange for hundreds of Palestinians held in Israel. The collapse of the talks led Israel to examine ways of getting tougher with Hamas, including imposing harsher conditions for detainees. Among the steps being considered are limiting cash transfers to prisoners, restricting their access to television and radio, reducing visiting rights and opportunities for education as well as limiting contact between the prisoners. Israel is also considering tightening the crippling blockade it has imposed on the Gaza Strip since Hamas took control in June 2007. Senior Hamas leader Salah Al-Bardawil claimed the West Bank arrests aimed at pressuring the Islamist group to cave in to Israel's demands in the prisoner swap negotiations. “It is a flagrant attempt to put pressure on Hamas and force it to make concessions and accept an exchange of prisoners without Israel having to pay the price,” Bardawil said in a statement published on the Hamas website.