DAMASCUS — The chief of the United Nations relief agency supporting Palestinian refugees said Tuesday he is “deeply disturbed and shaken” by the despair and destruction he’d seen in a besieged camp in the Syrian capital.

The Yarmouk refugee camp, located in southern Damascus, is an opposition enclave under the tight blockade of forces loyal to President Bashar Assad. More than 100 people have died in Yarmouk since mid-2013 as a result of starvation and illnesses exacerbated by hunger or lack of medical aid, according to UN figures.

Filippo Grandi, the Commissioner General of UNRWA, was visiting Yarmouk as the relief agency resumed food distribution there. UNRWA shipments to the camp have been disrupted for months, sometimes cut off for weeks at a time, and Yarmouk has suffered from crippling shortages of food and medicine.

“I am deeply disturbed and shaken by what I observed,” Grandi said in a statement. Palestinian refugees to whom he spoke in Yarmouk Monday were “traumatized by what they have lived through.”

The extent of damage to the refugees’ homes was shocking, he also said, adding that many Palestinians in Yarmouk need immediate support, particularly food and medical treatment.

Yarmouk is the largest of nine Palestinian camps in Syria. Since the camp’s creation in 1957, it has evolved into a densely populated residential district just five miles (eight kilometers) from the center of Damascus. Several generations of Palestinian refugees have lived there.

About half of the camp’s 150,000 residents have fled since fighting erupted in mid-December 2012, according to estimates of UNRWA, which administers Palestinian camps in the Middle East. Some sought refuge in neighboring Lebanon, and others found shelter in UNRWA schools in Damascus and other Syrian cities.

When the uprising against Assad erupted in March 2011, most Palestinians stayed on the sidelines. As the revolt turned into a civil war that reached Yarmouk in December 2012, most residents backed the rebels and some even took up arms to fight Assad’s troops and pro-government Palestinian fighters.

Also on Tuesday, the leader of a powerful al-Qaeda-linked jihadi group in Syria gave a rival al-Qaeda breakaway group a five-day ultimatum to seek arbitration by leading clerics or be expelled from the region.

Abu Mohammed al-Golani, leader of the Nusra Front, warned the Islamic State of Iraq and the Levant that it would be driven both from Syria and “even from Iraq” if it rejected the results of arbitration “under God’s law.”

The threat came in an audio message produced by the Nusra Front media arm al-Manara al-Baydha and was posted on militant websites Tuesday.

Al-Golani’s ultimatum came two days after the killing of Abu Khaled al-Suri who acts as al-Qaeda chief Ayman al-Zawahri’s representative in Syria. He was believed to be assassinated by two ISIL suicide bombers.

Copyright 2014 The Associated Press.