The Palestinian Authority on Sunday expressed outrage over the arrest by the IDF of Aziz Dweik, speaker of the Palestinian Legislative Council, and called on the international community to exert pressure on Israel to release him and other Hamas officials. PA Prime Minister Ismail Haniyeh accused Israel of trying to "blackmail" the Hamas government by arresting 27 PLC members and eight ministers, in addition to Dweik, who was picked up from his home in Ramallah late Saturday night. "They [Israel] are trying to disrupt the work of the democratically elected government and to force the Palestinians to surrender," Haniyeh told reporters in Gaza City. He also accused Israel of "state terrorism" and criticized the Arab world for failing to help the Palestinians and Lebanese. "The Arab countries could do a lot to stop the Israeli massacres and the campaign against Hamas ministers and parliamentarians, but they aren't doing anything," he said. Meanwhile, tensions between Hamas and Fatah intensified following the assassination of Muhammad Musat, commander of the PA's Military Intelligence Force in the northern Gaza Strip. Musat was killed when unidentified gunmen opened fire at his car near the Jabalya refugee camp. Fatah sources accused Hamas of being behind the assassination. Musat is the fifth Fatah-affiliated security official to be killed by purported Hamas gunmen in the Gaza Strip in recent weeks. Haniyeh said that the arrest of Dweik would not stop his government or the PLC from carrying out their responsibilities. "These measures have only united the Palestinians and rallied them behind their government," he said. Dweik is the most senior Hamas leader to be arrested by the IDF since the kidnapping of Cpl. Gilad Shalit in June. PLC members said the Israeli campaign against Hamas leaders had effectively paralyzed the Hamas-dominated parliament. Shalit is being held in the Gaza Strip by Hamas and other groups. Haniyeh said he supported resolving the Shalit issue through negotiations. "This case should be resolved through diplomacy and negotiations as a humanitarian and political issue," he said. Haniyeh said that while his government was not directly involved in the case, he was in touch with PA President Mahmoud Abbas, Egypt and Turkey in an attempt to resolve the crisis peacefully. Hours after his arrest, Dweik was interviewed by phone from his cell at the IDF's Ofer base by the Palestinian news agency Ramattan. He said his arrest was a "sign of Israel's failure and impotence" and that Israel was "bringing itself closer to destruction by continuing with its policy of aggression and oppression." Dweik rejected the possibility of exchanging him and his colleagues for Shalit. "We were all kidnapped and we won't agree to become part of a prisoner swap with Israel," he said. "Those who should be included in the prisoner exchange are those who have spent many years in prison for the sake of their homeland and their people's freedom," he said, referring to Palestinian security prisoners in Israeli jails.