The UN’s agency for Palestinian refugees on Monday appealed for emergency funds to provide aid to nearly half a million Palestinians affected by the war in Syria.

The United Nations Relief and Works Agency, UNRWA, said almost all the estimated 450,000 Palestinian refugees still inside Syria are in “critical need” of humanitarian aid in order to survive.

It said it needed $411 million (NIS 1.58 billion) to support the Palestinians inside Syria as well as 47,000 others who have fled to neighboring Jordan and Lebanon.

UNRWA said that 43,000 Palestinians in Syria are in hard-to-reach or besieged areas cut off by fighting, including the Yarmouk camp in Damascus.

“It’s a clear violation of international humanitarian law to deny people who are vulnerable, as a result of displacement, conflict or war, humanitarian assistance,” the agency’s outgoing Syria head Matthias Schmale told AFP.

UNRWA said tens of thousands of Palestinians who have fled to Lebanon and Jordan also needed aid to make ends meet.

“Some Palestinian refugees who have not asked for UNRWA funds before are looking to us today to help them cover their most basic needs,” said Hakam Shahwan, the agency’s ad-interim Lebanon director.

He said some 31,800 Palestinian refugees from Syria are among an influx of some one million Syrians who have taken refuge in Lebanon since Syria’s conflict began almost six years ago.

“That adds to the assistance we have to provide to the Palestinian refugees,” Shahwan told AFP.

Lebanon was already home to around 450,000 Palestinian refugees, mostly the descendants of those who fled their homes when the State of Israel was created in 1948, or during subsequent conflicts.

Syria’s conflict began in March 2011 with anti-government protests and has evolved into a complex civil war that has killed over 310,000 people and displaced more than half the country’s population.