Palestinian Authority security forces were put on high alert Wednesday following threats by Hamas against its senior officials, PA security sources told The Jerusalem Post. The PA leadership was taking Hamas's threats seriously and had ordered its security forces to be prepared to foil any attempt to harm PA figures, the sources said. Additional bodyguards have been assigned to a number of top PA officials in the West Bank, and security had been beefed up around the homes of PA President Mahmoud Abbas and other senior officials in Ramallah, the sources said. Leaflets distributed over the past few days by Hamas's armed wing, Izzadin Kassam, threatened to target top Palestinian leaders in the West Bank for "collaborating with Israel." The leaflets specifically referred to Abbas, PA Prime Minister Salaam Fayad, PLO executive committee member Yasser Abed Rabbo and top Fatah officials Azzam al-Ahmed and Ahmed Abdel Rahman, as well as Tayeb Abdel Rahim, a senior adviser to Abbas. The Hamas threats came in response to the arrest of dozens of Hamas figures and supporters by Abbas's security forces in the West Bank over the past few days. The PA crackdown on Hamas came in the aftermath of the arrest of some 150 Fatah members and supporters by Hamas security forces in the Gaza Strip over the past four days. Altogether, more than 250 Palestinians have been arrested by both Hamas and the Fatah-dominated PA security forces since Friday, when a mysterious explosion killed five Hamas men in Gaza City. "The continued arrests of Hamas figures in the West Bank will lead to a new intifada against the [Israeli] occupation and its agents," read a statement published Izzadin Kassam. Meanwhile, a Hamas delegation that visited Cairo this week is expected to leave the Egyptian capital on Thursday after failing to achieve progress on the case of kidnapped IDF St.-Sgt Gilad Schalit, a Hamas official in Gaza City told the Post. The delegation was headed by Musa Abu Marzouk, the No. 2 in the Hamas leadership in Syria. The Hamas leadership in the Gaza Strip was represented by Jamal Abu Hashem. According to the official in Gaza City, the Hamas representatives held talks with several Egyptian government officials on the latest developments surrounding the case of Schalit and the Gaza cease-fire with Israel. The Hamas representatives renewed their demand to reopen the Rafah crossing between Gaza and Sinai so as to pave the way for holding indirect talks with Israel on a prisoner swap, the official in Gaza City said. "As long as the Rafah border remains closed, there will be no progress on the case of Schalit," he stressed. "The delegation is returning tomorrow [Thursday] without an agreement on a prisoner exchange with Israel," the official said. "From what we understand from our Egyptian brothers, Israel is still refusing to accept all our demands, including the release of 1,000 prisoners in three phases." He said the Hamas delegation received an official invitation from the Egyptians to attend inter-Palestinian discussions to end the crisis in the Palestinian arena. "The Egyptians want to host a conference for Palestinian reconciliation," he said. "Hamas will study the invitation and give its reply in the coming days."