Under pressure from the Palestinians to patch up their differences, Hamas and Fatah leaders arrived in Saudi Arabia Tuesday for crucial talks on ending internal strife and forming a unity government. The leaders of the two [arties expressed fear that the failure of the summit would lead to renewed fighting. The Fatah delegation is headed by Palestinian Authority Chairman Mahmoud Abbas, while the Hamas team is led by the movement's Syria-based leader, Khaled Mashaal. PA Prime Minister Ismail Haniyeh of Hamas will also participate in the discussions, which are expected to last three days. Sources close to Abbas said that if the summit ended without an agreement, he would carry out his threat to call early presidential and parliamentary elections. "This is the last chance for Hamas," the sources added. The sources voiced concern over a report in a Kuwaiti newspaper on Tuesday to the effect that Syrian President Bashar Assad had warned Mashaal against making concessions to Fatah. Upon their arrival, Abbas and Mashaal met separately with Saudi King Abdullah bin Abdel Aziz and briefed him on the latest developments in the PA-controlled territories. Saudi officials will not participate in the talks between the two Palestinian parties. Palestinian officials in Ramallah and Gaza City hailed the Saudi initiative to host the conciliatory talks, noting that Saudi Arabia could have tremendous influence on the two parties. "The Saudis have a lot to offer," said one official. "Apart from providing financial aid to the Palestinians, they can use their good offices with the US and Europe to employ pressure on Israel." However, the talks in Mecca were overshadowed by the controversial Israeli excavations near the Temple Mount. Both Abbas and Mashaal were quick to condemn the excavations as an "assault on the Aqsa Mosque," urging the Arab and Islamic world to intervene to halt the work. On the eve of the talks, Fatah and Hamas officials expressed hope that the discussions would result in an agreement on the formation of a Palestinian unity government. Palestinian ambassador to Saudi Arabia, Jamal Shobaki, said the talks were designed to reach an agreement on a unity government that would be able to persuade the international community to lift financial sanctions imposed on the Palestinians in the aftermath of Hamas's rise to power. "Statements made by leaders of the two parties show that they are sincere and serious about reaching an agreement," he said. Before leaving the Gaza Strip through the Rafah border crossing, Haniyeh pledged to do his utmost to make the summit succeed. "There are many sticking issues," he admitted. "But with good intentions on both sides, I believe we will be able to overcome the difficulties." Hamas representative Khalil Abu Leilah said although Hamas was ready to make far-reaching concessions at the summit, the movement would not accept the conditions of the Quartet, namely recognizing Israel's right to exist and renouncing violence. "Hamas will make a huge effort to enable the formation of a unity government," he said. "But we will not accept the conditions of the Quartet because they are intended to humiliate the entire Arab and Islamic world." However, other Hamas leaders appeared to be less optimistic. Hamas legislator Yehya Mussa said his movement was unhappy to see some Fatah leaders participate in the talks. "The presence of people like Muhammed Dahlan, Nabil Amr and Azzam al-Ahmed does not bode will," he said, referring to the three top Fatah officials. "The three are responsible for the continued tensions between Fatah and Hamas."