Yasser Arafat's guerrillas and Syrian-backed rivals dueled Friday with mortars and rockets over two devastated refugee camps in Beirut. Police said 10 people were killed and 34 wounded.

With Friday's casualties, 63 people have been killed and 249 wounded in 15 days of clashes at the camps of Chatilla and Bourj el-Barajneh on Beirut's southern edge.By police count, 112 people have been killed and 502 wounded since the clashes erupted May 1.

A police spokesman said the intensity of the fighting escalated sharply at about 5 a.m., when fighters from Col. Saeed Mousa's Fatah-Uprising hammered the two camps with mortars and rockets at a pace of five shells per minute.

Defenders from Arafat's Fatah group, the main component of the Palestine Liberation Organization, responded in kind, the spokesman said.

Residents of Beirut woke up to the booms of shell blasts that resounded across the city. Smoke billowed from the two shantytowns as ambulances, their sirens wailing, raced to evacuate casualties.

Arafat's loyalists dislodged Mousa's followers from the two camps in previous rounds of fighting. The Fatah-Uprising fighters have regrouped along the Syrian-controlled edges of the shantytowns and launched a series of abortive attacks to regain lost territory.

The police spokesman, who cannot be named in line with standing regulations, said the tiny camp of Chatilla took the brunt of the Fatah-Uprising shelling from positions in Syrian-policed West Beirut.

"It appears they (Mousa's forces) are trying to demolish what is left of Chatilla," the spokesman said.

The two camps suffered extensive damage in repeated attacks by Israel and Syrian-backed Shiite Moslem militias beginning in 1982.

The fighting raged despite a Libyan-brokered truce announced in Tripoli Thursday.

The truce, reached in a meeting between Libyan officers and representatives of neutral Palestinian guerrilla factions, called on the warring factions to return to positions they held before the fighting started May 1.

Fatah-Uprising, in a statement, accused Arafat of provoking the clashes at the two camps to "sabotage Syria's role ... in order to be acceptable to America."

Fatah and the mutineers have been fighting in Beirut despite a reconciliation meeting between Arafat and Syrian President Hafez Assad in Damascus last April.