Palestinian President Mahmoud Abbas has long insisted that Palestinians stay out of the Syrian conflict. It was not immediately clear why Majdalani, sent by Abbas to Damascus to deal with the Yarmouk crisis, came out in support of Palestinian military involvement in Syria.

The contradictory comments exposed internal Palestinian disagreements on how to handle the growing crisis in Yarmouk, where thousands of civilians are trapped under appalling conditions.

Wasel Abu Yousef, a senior PLO official based in the West Bank town of Ramallah, said Friday that negotiating safe passage for Yarmouk's besieged residents and for humanitarian supplies is preferable to military action.

"We know that if the [Syrian] army, with its planes and tanks, would interfere, this would mean the complete destruction of the camp," he said.

A Damascus-based Palestinian official, Khaled Abdul-Majid, said the back and forth was not helping Yarmouk. He said the PLO was backing away from earlier statements "as a result of pressure from external sides." He did not elaborate, but said Damascus-based Palestinian factions will stick to the agreement reached on joining Syrian troops in driving ISIL militants out.

ISIL fighters overran much of Yarmouk last week, establishing a foothold in the Syrian capital for the first time. The incursion is the latest trial for Yarmouk's estimated 18,000 remaining residents, who have already suffered through a devastating two-year government siege, starvation and disease.

Residents say there is barely enough food and water, and hospitals have long run out of drugs and supplies.

A U.N. official, Chris Gunness, said he was concerned the violence was intensifying and said all diplomatic, economic and religious levers must be used to influence the parties on the ground.

"Yarmouk is at the lower reaches of hell. It must not be allowed to descend further," he said.

Reporters visiting Yarmouk on a government-escorted tour Thursday saw the empty shells of buildings at the camp's northern entrance. In its dusty and deserted streets, a few sheep foraged in the rubble.

Yarmouk was established in 1957 as a refuge for Palestinians forced from their homes during the 1948 war that resulted in the creation of Israel. In subsequent decades, it grew into a built-up residential area housing tens of thousands of Palestinians and Syrians.

A Syrian government official has said driving ISIL out of Yarmouk by force is a top priority and the only option.

U.N. Secretary General Ban Ki-moon said the mayhem has turned Yarmouk into "the deepest circle of hell."

"A refugee camp is beginning to resemble a death camp," Ban told reporters at the U.N., adding that the residents, including 3,500 children, are being used as human shields by armed elements inside Yarmouk and government forces outside it.

Also Friday, activists said Syrian government airstrikes on the northern city of Raqqa, which is ISIL's de facto capital, killed at least four people.

The Raqqa Media Center, which operates in areas under ISIL control, said the airstrikes on residential areas killed four and wounded 15, while the Local Coordination Committees said four were killed and an unspecified number were wounded.

The Associated Press