Rival Palestinian leaders traded accusations of coup and assassination attempts on Tuesday as intensified factional violence once again threatened to plunge Gaza into civil war.

Heavy gun battles erupted in several locations as Hamas's armed wing stepped up attacks on rival Fatah's security positions. Several Fatah commanders loyal to President Mahmoud Abbas expressed frustration with a lack of orders to fight back.

A Palestinian youth looks out of the damaged house of Fatah leader Jamal Al-Jedyan on Tuesday after it was attacked and burned by militants in northern Gaza. Gunmen, apparently from Hamas, laid siege to the house of the senior Fatah official late Monday, then dragged him outside and killed him, security officials said. Medics reported that he was hit with 45 bullets.
(Wissam Nassar-MannImages/Associated Press)

After several hours of intense fighting, some 200 Hamas fighters captured the headquarters of Fatah-allied forces in northern Gaza, where about 500 security officers were holed up. A Fatah security official confirmed the building had been lost and said at least 10 people were killed and 30 wounded.

At least four smaller security bases were overrun by Hamas in the southern town of Khan Younis.

Earlier Tuesday, a rocket-propelled grenade struck the home of Hamas Prime Minister Ismail Haniyeh in the Shati refugee camp in Gaza City, the second attack on his residence in as many days.

Hamas called the attack an assassination attempt by Fatah. There were no injuries.

Abbas, who is in the West Bank, appealed for a new ceasefire and accused Hamas of "planning to stage a coup against the legitimate institutions" and trying to gain control of Gaza by force.

Earlier, four mortar shells hit Abbas's Gaza City compound, but caused no injuries.

In the West Bank, Fatah gunmen kidnapped a deputy cabinet minister from
Hamas and threatened to retaliate to the attacks by killing other Hamas leaders.

'Gaza is burning now'

Later Tuesday, Haniyeh issued his own appeal for an end to the fighting and resumption of negotiations, but there was little indication the factions' forces on the streets were heeding either leader's calls.

The battles once again brought civilian life in Gaza to a standstill, as residents locked themselves indoors. University exams were cancelled, despite an earlier ceasefire called to allow students to finish the school year in relative peace.

"Gaza is burning now by the hands of Palestinians," journalist Hamza el-Attar told CBC News Tuesday in a telephone interview. "Bullets are everywhere."

Hopes of a ceasefire to halt clashes that have killed at least 18 people in the last 24 hours appeared crushed as exasperated Egyptian mediators said the bitter rivals turned down an appeal to meet for truce talks.

A Fatah spokesman said the movement would decide in the next few hours whether to stay in the three-month-old coalition government.

The most recent violence has seen people on both sides shot at close range in street executions, while others died in shootouts, including one inside a hospital.

The violence stems from a dispute over which side would control security forces as part of the coalition government agreement between Hamas and Fatah.

At least 80 people have died in the factional battles since May.

With files from the Assocated Press