Israel has informed Hamas through a number of Arab mediators that it wants to resume secret negotiations over the release of IDF soldier Cpl. Gilad Schalit, sources close to Hamas said Wednesday. The sources told The Jerusalem Post that Israel had also told Hamas that it was not planning to target the movement's leaders and that the killing of Hamas leader Mahmoud Zahar's son Tuesday was not intentional. According to the sources, the Israeli message was delivered to Hamas following Tuesday's IDF operation in Gaza City in which 19 Palestinians, most of them Hamas members, were killed. The sources refused to reveal the identity of the mediators who reportedly delivered the message to Hamas. However, other sources in the Gaza Strip pointed out that Egypt, Qatar and Saudi Arabia had all been involved in behind-the-scenes talks with Hamas over reaching a prisoner exchange with Israel. A senior source in the Prime Minister's Office said he had no knowledge of any such messages being passed to Hamas. A top Hamas official in the Gaza Strip claimed that Tuesday's IDF operation had had a "negative impact" on the secret talks over the release of Schalit. He said the two sides had been very close last week to striking a deal on a prisoner exchange. "Now we will have to raise the price for the soldier's release because of the continued Israeli aggression," he added. "Israel's actions are only complicating the case of Schalit." Also Wednesday, the Hamas official in charge of negotiations over the captured soldier, Osama Mazini, said that if Israel continues to intensify its military campaign in the Gaza Strip, Hamas will change it's policy regarding Schalit. "We will not be able to quietly take the continuation of assassinations and raids that the enemy is conducting in the Gaza Strip and the West Bank," Mazini said during an interview on the Hamas television station, Al-Aksa, warning that there is "no doubt" that such activity "affects the Schalit affair." Mazini said that "it is very possible that we will cut off contact," warning that this will turn the issue into something similar to that of missing IAF navigator Ron Arad. Following Hamas's threats, MK Binyamin Ben Eliezer (Labor) said Thursday that the group will not follow through with its threat to harm captured Schalit because the captured soldier is only bargaining chip against Israel. "The main asset in the hands of Hamas today is Gilad Schalit. We should treat what [Hamas] said with skepticism," Eliezer, a former defense minister who is currently a member of the security cabinet, told Army Radio. "Today, Hamas has a major interest in keeping Gilad safe. As far as they are concerned, he is the only asset they hold against Israel." Hamas's Syria-based leader, Khaled Mashaal, echoed the sentiment of his Gazan counterparts during a press conference in Damascus on Wednesday. Addressing Israel, Mashaal said, "You will pay a heavy price for your crimes against the Palestinians. You will never break the will of the Palestinians, because we will never surrender. We will never give up the right of return or our right to Jerusalem. "What you are doing now will deprive you of achieving your goal. There won't be any calm or a prisoner exchange for Gilad Schalit," he warned. He said that in any case, Schalit wouldn't be released until Israel agreed to free all the prisoners Hamas was demanding in the context of a prisoner swap. Referring to Tuesday's IDF operation, Mashaal said that "Palestinian blood won't bring peace or security to Israel." Israel, he added, would become less secure if it continued to perpetrate "crimes" against the Palestinians. Mashaal also held US President George W. Bush responsible for the upsurge in IDF operations in the West Bank and Gaza Strip. "Bush came to the region to provide a cover for Israel's crimes," he said. "During his visit, Bush repeatedly incited against the Palestinians and so-called terrorism. He didn't come to make peace, but to trigger war." The Hamas leader launched a scathing attack on the Palestinian Authority leadership in Ramallah for failing to call off peace talks with Israel in response to Tuesday's killings. "It's [not] enough to issue condemnations [against Israel]," he argued. "The Palestinian leadership should halt the negotiations because they are pointless and because of Israel's actions." Meanwhile, the death of Hussam Zahar has boosted the standing of his father, Mahmoud Zahar, who is now being hailed by many Palestinians and Arabs for having sacrificed his two sons in the fight against Israel. Zahar's elder son, Khaled, was killed in a 2003 IAF air raid on his house in Gaza City. Last year, Zahar's son-in-law, Ahmed Awad, was also killed by the IDF. Awad was a senior member of Hamas's armed wing, Izzadin Kassam. In 1996, the PA security forces arrested Zahar several times after accusing him of inciting to violence and making derogatory remarks against former PLO chairman Yasser Arafat. In detention, his interrogators shaved off his beard to humiliate him. Thousands of Palestinians, including PA Prime Minister Salaam Fayad and many Fatah leaders, have offered their condolences to Zahar over Hussam's death. Even Fatah-affiliated media outlets expressed sympathy for Zahar, who until now had been considered a sworn enemy of Fatah. One Fatah Web site that had regularly run a picture of Zahar depicting him as a devil has removed it following his son's death. The IDF operation has also brought Zahar closer to Hamas Prime Minister Ismail Haniyeh. The two, who appeared together in public in the past 24 hours, were reportedly engaged in a sharp power struggle over the past year. "For many Palestinians and Arabs, including those who never liked the man, Zahar has become a real hero," said a Palestinian journalist in Gaza City. "They are saying that while the sons of most Arab leaders are busy making a fortune and entertaining themselves in the US and Europe, Zahar has sacrificed his sons in the battle against Israel." Herb Keinon contributed to this report.