Renewed Palestinian factional fighting killed seven people on Monday in Gaza, where gunmen fired on government offices forcing ministers to interrupt a cabinet meeting.
In violence late afternoon, three people were killed in gunbattles between rival Hamas and Fatah movements in the northern town of Beit Hanun and one person in a fight near a hospital in Gaza City, medics said.
Earlier, gunmen on the rooftop of an adjacent building fired on government offices as prime minister Ismail Haniya of Hamas chaired the weekly cabinet meeting, forcing the ministers to flee the premises.
"The prime minister interrupted the meeting and left the premises with the rest of the ministers," an official at Haniya's office said, accusing fighters from rival Fatah of being behind the gunshots.
The gunbattles and shootings were the latest breach of the newest truce agreed by the two rivals with Egyptian mediators, who for months have been trying to calm increasingly violent tensions between the two sides.
In a grim warning that the violence could spiral further, Hamas spokesman Fawzi Barhum said his movement "has decided to punish all the murderers and criminals" after having given the latest ceasefire a chance.
"Killing them is the only dissuasive response," he said, adding that the office of sports and youth minister Bassem Naim, of Hamas, also came under fire.
Overall, 13 people have been killed in the lawless territory in the new bout of internecine bloodshed between Islamist Hamas and secular Fatah that first flared on Thursday.
More than 160 people have been killed since the first major bout of violence erupted in December.
Palestinian president Mahmud Abbas earlier called for an end to the bloodshed after warning last week that the strife had left Palestinians on the brink of a civil war and was as damaging, if not more so, than the 40-year Israeli occupation.
"What's happening in Gaza is regrettable and very harming. Both parties are working seriously with the Egyptian brothers to put an end to it," Abbas told reporters in Ramallah in the occupied West Bank.
The factional fighting in one of the world's most densely populated areas, along with renewed Israeli attacks in response to militant rockets, have threatened to sink international efforts to jumpstart the dormant Middle East peace process.
The violence has rattled the unity government that the two parties formed in March with the hope that it would halt the bloodshed and pave the way for an end to a crippling Western aid boycott.
The level of animosity between the rivals locked in a bitter power struggle has reached new highs after more than a year of rising tensions that followed Hamas's rout of Abbas's long-dominant Fatah in a parliamentary poll in January 2006.
Among those killed in the past few days was a Fatah member who was flung to his death off an 18-storey building by Hamas supporters, and imam Mohammed al-Rafati, a brother of a local Hamas leader, who was shot dead at his mosque by Fatah men, security sources said.
A bullet-riddled body of a Fatah member was found on a Gaza street early on Monday, his legs tied, in what a spokesman for Fatah said was an "execution" by Hamas men.
Early Monday afternoon, a 20-year-old man was killed by gunfire in northern Gaza, but his identity was not immediately known, medics said, and a 23-year-old Hamas militant was killed in a gunbattle with Fatah men in Beit Hanun.
Gaza militants on Monday launched a fresh volley of rockets into Israel, without causing injuries, nearly a month after the Jewish state resumed deadly air and ground operations on the territory in response to the fire.
Israeli Prime Minister Ehud Olmert on Sunday vowed to keep hitting Gaza, a day after militants carried out the first cross-border raid into Israeli territory in nearly a year, which left one militant dead.
The raid marked the first such operation by Gaza militants since June 25, 2006, when gunmen tunnelled out of Gaza and attacked an army post, killing two soldiers and capturing a third, Corporal Gilad Shalit, who remains in captivity.
Israeli strikes have killed 16 civilians and 39 militants since being resumed on May 16 following a sharp increase in rocket fire. Two Israeli civilians have been killed and more than 20 people wounded by the more than 310 projectiles launched into the Jewish state since May 15, the army said.