Gunmen from the rival Hamas and Fatah movements battled in Gaza City for a third straight day Saturday, firing mortars and grenades in clashes that killed two men in the increasingly bloody power struggle over the Palestinian government, according to The Associated Press. The deaths brought to 20 the number of Palestinians killed since late Thursday, with at least 66 people wounded and efforts to forge a coalition government at a standstill. The latest fighting, which started late Thursday after a Hamas activist was killed in a bombing, has been among the deadliest in nearly two months of clashes. Palestinian Prime Minister Ismail Haniyeh of Hamas issued a statement calling for calm. But in a clear jab at the moderate Palestinian president, Mahmoud Abbas of Fatah, Haniyeh criticized «trouble makers who are trying to veer away from the path of our people» by receiving «dirty American funding and arms.» The White House is seeking some $85 million (¤66 million) to help bolster Abbas' forces. Abbas' spokesman, Nabil Abu Rdeneh, called for an end to the infighting and a resumption of unity talks. His comments were carried by the official WAFA news agency. The violence has been fueled by Abbas' pledge to call early elections if the unity talks between Hamas and Fatah fail. Abbas, who is traveling in Europe, said this week he would move forward with his election plan if the coalition talks don't produce results within three weeks. Hamas, which defeated Fatah in parliamentary elections last year, opposes a new vote. Streets in the hardest-hit neighborhoods were deserted Saturday, and only bakeries and groceries opened for business. Gaza City's main outdoor market was closed. Al Azhar University called off exams scheduled for Saturday, and the Hamas-controlled Interior Ministry, which oversees several security forces, told its employees to go home. A gun battle erupted Saturday near the Islamic University, killing one man, according to hospital officials. In a firefight elsewhere in the city, a Palestinian policeman was killed. Before dawn Saturday, Hamas gunmen fired mortars at the Abbas-allied Preventive Security Service headquarters and at the home of the force's chief, Rashid Abu Shbak, officials said. In fighting around the compound on Friday, six Hamas gunmen were killed and a seventh died Saturday of wounds sustained in that battle, said Hamas spokesman Ayman Taha.