Palestinian gunmen on Saturday stopped a car carrying a Hamas Cabinet minister and opened fire at the vehicle, officials said, sparking a roadside gunbattle that underscored the lingering tensions between the rival Fatah and Hamas movements as they try to put together a coalition government. No one was hurt in the shootout, which came a day before Palestinian Authority Chairman Mahmoud Abbas was expected to discuss the unity deal at a summit with Prime Minister Ehud Olmert. Hamas officials said Cabinet minister Wasfi Kibha, the target of the attack, was traveling to a ceremony in the West Bank town of Tubas when his car was stopped at a nearby village by three gunmen. The shooters opened fire, hitting the vehicle four times, security officials said. Hamas forces quickly rushed to the scene, there was an exchange of fire, and the three gunmen fled, Hamas officials said. The ceremony, where Kibha and another minister planned to dedicate a new Education Ministry building, was canceled. Hamas accused Palestinian security officials with ties to Fatah of being behind the attack. Security officials said they were aware of the incident but did not know who was responsible. Last month, Abbas of Fatah and top officials from Hamas agreed to form a unity government in a last-ditch attempt to halt months of bloody infighting. While the agreement ended the latest wave of violence, tensions remain high as the sides try to finalize their power-sharing deal. An initial deadline for wrapping up the power-sharing deal expired on Friday. But in a widely expected procedural step, Abbas gave PA Prime Minister Ismail Haniyeh an additional two weeks to cobble together a government. In other violence Saturday, members of the Aksa Martyrs Brigades opened fire at Palestinian security headquarters and forced government offices to close in Jenin, demanding that they receive long-overdue salaries promised by the government. About 20 gathered outside the security building, periodically firing rounds. After about an hour, the shooters retreated, saying they had received assurances that their demands would be met. No injuries were reported. After winning election in 2005, Abbas promised police jobs to hundreds of militants in order to bring the violent groups under control. The participants in Saturday's protest said they were paid several times, but stopped receiving salaries last year. Zakariye Zubeydi, the local Al Aksa leader, said he ordered his men to halt their fire after the government agreed to resume payments to families of men killed in violence with Israel, and to open negotiations on paying the members their back salaries. "We solved the problem. We stopped shooting," he said.