At least three mortar shells were fired at Palestinian Authority Mahmoud Abbas's headquarters in Gaza City on Sunday. One of them hit a nearby house, wounding two civilians. PA security officials accused Hamas's "Executive Force" of launching a massive attack on the compound with the aim of occupying it. Before the mortar attacks, fierce fighting erupted near Abbas's headquarters between his Force 17 "Presidential guard" and Hamas gunmen. A 19-year-old woman, Hiba Musbah, was fatally shot in the chest and five Force 17 officers were wounded. Abbas phoned US Secretary of State Condoleezza Rice and briefed her on the latest developments. A source close to Abbas said he told Rice he was determined to pursue his plan to get rid of the Hamas-led government as soon as possible. "The governments of Jordan and Lebanon have sent us messages in the past 24 hours saying they are very worried that the fighting could spill over into their countries," a top PA official told The Jerusalem Post. "They urged us to work to calm the situation because they don't want trouble at home. There is no problem with the Palestinians in Syria because most of them are opposed to President Mahmoud Abbas and Fatah, anyway." Official figures put the number of Palestinian refugees in Jordan at 1.5 million, but unofficial estimates put the number at closer to 3.5m. There are nearly 500,000 Palestinian refugees in Lebanon. Another official told the Post that Jordanian authorities have beefed up their presence around the kingdom's refugee camps for fear of clashes between Hamas and Fatah supporters. "Tensions inside the camps are running very high," the official said. "The Jordanians fear that any outburst of violence will destabilize the regime." According to the official, Fatah activists in a number of refugee camps in Lebanon contacted Abbas's office over the past few days to report that the situation there was "on the verge of an explosion." At the time of the attack on his headquarters, the first of its kind against the offices of the PA chairman, Abbas was meeting with members of the PA Central Election Commission to discuss his decision to hold early parliamentary and presidential elections. No date was set for the vote and election officials said they would need at least three months to prepare for new elections. Earlier, Hamas gunmen fired several shots at Abbas's private residence in Gaza City. No one was hurt. The attacks on Abbas's headquarters and home came shortly after Hamas accused Abbas's security forces of trying to assassinate PA Foreign Minister Mahmoud Zahar of Hamas. Taher Nunu, spokesman for the PA Foreign Ministry, said attackers fired several shots at Zahar's car as he was leaving his office in the Tal al-Hawa neighborhood of Gaza City. One of Zahar's bodyguards was lightly wounded. "The minister has escaped an attempt on his life," Nunu said. "Snipers deployed on nearby rooftops opened fire from automatic weapons at the minister's car." In a move that was condemned by Hamas as the beginning of a "military coup," hundreds of Fatah gunmen and Force 17 members occupied the offices of the Hamas-run ministries of Agriculture and Transportation in Gaza City. The attackers expelled all employees and announced that the ministries would remain closed on instructions from Abbas. The ministries issued a statement describing the takeovers as tantamount to a military coup and accused Abbas loyalists of serving the interests of Israel and the US. Another seven people were wounded when Hamas gunmen fired at a Fatah rally in the northern Gaza Strip. Late Saturday night, some 300 Hamas gunmen raided a Force 17 base in Gaza City and beat the 20 security officers there. The attackers also destroyed a vehicle and set fire to tents. The attackers fled when reinforcements from Force 17 approached the area. Fatah spokesman Jamal Nazzal said the attackers accused Force 17 of standing behind the assassination attempt on PA Prime Minister Ismail Haniyeh last Thursday. Following an emergency meeting in Gaza City, the Hamas-led cabinet reiterated its strong opposition to Abbas's decision to call early parliamentary and presidential elections and said it would boycott the vote. Referring to Abbas's announcement over the weekend, the cabinet said: "This was not a speech for unity; it was an inflammatory and sarcastic speech that underestimated the sacrifices of our people." AP contributed to this report.