On the eve of a summit in Mecca between Palestinian Authority Chairman Mahmoud Abbas and Hamas leader Khaled Mashaal, Fatah gunmen here kidnapped Arafat Nasser, the director of PA Interior Minister Said Siam's office. Witnesses said Nasser was abducted as he was about to leave his office in the Irsal neighborhood north of the city. His bodyguard, Tarek Ghaithan, was shot in the legs by the gunmen. The former director of Siam's office, Ihab Ghaithan, was shot in the legs by Fatah gunmen last month as part of the power struggle between Fatah and Hamas. He is the brother of the bodyguard who was shot during Monday's kidnapping. The latest incident is apparently linked to Sunday's abduction in the Gaza Strip of Ashraf Dahlan, a nephew of senior Fatah leader Muhammad Dahlan. Fatah activists here said Nasser would only be released if Hamas agreed to free Dahlan's nephew. Fatah spokesman Jamal Nazzal strongly condemned the kidnapping of Dahlan's nephew and called for his immediate release. "This is a despicable act," he said. "Ashraf Dahlan has nothing to do with his uncle's political activities." In Gaza City, Hamas gunmen kidnapped Fatah activists Khader Afaneh and Hassan al-Bazam Monday. The gunmen also kidnapped Mahmoud Madhoun, a mentally retarded man from Beit Lahiya in the northern Gaza Strip. Fatah and Hamas gunmen briefly exchanged gunfire in parts of Gaza City, but no casualties were reported. In Nablus, Fatah gunmen severely beat Ammar Hanbali, a top Hamas activist, after their attempt to kidnap him failed. The latest violence, in addition to the ongoing war of words between Fatah and Hamas, may have a negative impact on the Abbas-Mashaal summit. The two are scheduled to meet in Mecca under the auspices of Saudi King Abdullah bin Abdel Aziz, in what is being described as a final attempt to avoid civil war in the PA. Fatah and Hamas leaders voiced optimism regarding the prospects of reaching a deal on a Palestinian unity government during the summit. They warned that failure would result in another wave of violence. "President Mahmoud Abbas is keen on achieving positive results at the summit," said PA negotiator Saeb Erekat. "We must help each other because no one is going to help us. We must face the reality and view matters with transparency. We need a unity government that will lead to the removal of international sanctions imposed on our people." PA Prime Minister Ismail Haniyeh of Hamas, who is expected to participate in the Mecca discussions, said his movement was sincere in its efforts to end the internal strife and form a coalition government. "The Palestinians have no choice but to unite," he told his ministers during the weekly cabinet meeting in Gaza City. "We hope the summit will end the tensions and fighting and consolidate national unity." Abbas adviser Nabil Amr described the summit as a last-chance event to achieve national unity among the Palestinians. "If the summit fails, we will have to call early elections," he said. "Then neither side will have an excuse to oppose early elections. We are going to Mecca with the intention of ending the fighting and bloodshed and reaching a deal on a unity government that would end the international sanctions." Haniyeh's political adviser, Ahmed Yusef, told the Maan news agency his movement was willing to make further concessions to enable the formation of a unity government. "We have already made many concessions on this issue," he said, referring to Hamas's agreement to cede control over key ministries.