BETHLEHEM (Ma'an) -- Most Palestinian factions have remained in Syria, with the exception of Hamas whose leaders have relocated, officials in Syria said Thursday.

Most Hamas leaders have fled Syria despite the movement's insistence that it was not seeking to move its politburo from Damascus. Only some local Hamas leaders in refugee camps remain, local officials told Ma'an.

Meanwhile, leaders of the Popular Front for the Liberation of Palestine, Fatah and Islamic Jihad stayed in Syria amid the bloody 16-month uprising against President Bashar Assad, the officials say.

Islamic Jihad Secretary-General Ramadan Shallah visited Syria in mid-July before heading to Cairo, sources in the movement told Ma'an.

Sheikh Nafeth Azzam, Islamic Jihad politburo member, has previously denied that the movement's leadership in Syria had moved its headquarters to Tehran.

Hamza Abu Shanab of the Gaza-based Palestinian Coalition for the Syrian Revolution told Ma'an on Tuesday that 105 families originally from the Gaza Strip had returned through Egypt's Rafah crossing since the weekend.

Palestinian sources in Syria told Ma'an that most of those who fled to Gaza were living in Syria as residents and not refugees, while some had been exiled to the country.

Residents of Yarmouk Palestinian refugee camp told Ma'an that forces loyal to Assad had shelled the Palestine Hospital in the camp twice on Thursday morning, causing a huge fire.

They said there had been heavy clashes between Assad's troops and opposition forces around the hospital since Monday morning, and that the Syrian army was targeting the hospital because medics were treating wounded from all sides, while Assad's regime only allowed its soldiers to be treated.

Residents added that fighting in Yarmouk was intensifying daily, and that the number of Palestinians killed was rising dramatically in camps across Damascus and in Daraa and Aleppo.

A resident of Yarmouk told Reuters on Thursday that the army seemed to be targeting sites on the edges of the camp, firing shells every minute. The bombardment started around 7 a.m. and was still going three hours later.

Yarmouk is the largest Palestinian refugee camp in Syria.

Assad has not spoken in public in more than a week since a bomb attack on his inner circle in Damascus, confining himself to appearing at formal televised events.

Western powers have been calling for Assad to be removed from office for months, but they fear that he will fight to the end.

At the UN Security Council, members blamed each other for rising violence in Syria. Western states pledged to seek an end to the conflict outside the world body, while Russia warned of "likely catastrophic consequences" with that approach.

Russia, an ally of Syria, and China have repeatedly blocked Western-backed Security Council resolutions on Syria.