A senior UN official on Monday said that the Syrian crisis is having dire effects on Palestinian refugees living in Syria, who face obstacles in receiving humanitarian assistance and are increasingly being drawn into the conflict.

Filippo Grandi, the commissioner general of UN Relief and Works Agency for Palestinian Refugees (UNRWA), told a press conference here that keeping schools open and health centers open is "an increasing challenge in a situation of growing insecurity, lack of access and other problems."

UNRWA, established in 1949 after the Arab-Israeli hostilities the year prior, operates under a core mandate to provide humanitarian assistance, including education and health services, to the approximate 5 million Palestinian refugees in the occupied Palestinian territory, Syria, Jordan and Lebanon.

But this is becoming more and more difficult in Syria for the 530,000 refugees who are registered in the Middle East country, concentrated mainly in the Yarmouk district, a suburb south of Damascus.

Access is a major concern. "It is becoming every day more difficult to reach them," said Grandi.

"This is not a clear-cut war," he said. "The dividing lines, the zones of control are extremely fluid and to operate convoys and movements of staff and people and goods through this shifting lines is extremely complicated and dangerous."

Additionally, the Yarmouk district has seen heavy fighting, as its close vicinity to the capital makes it a "strategic point of access" for government and rebel forces.

Last summer, "the conflict expanded," said Grandi. "It reached the areas inhabited by Palestinian refugees and inevitably they were more impacted."

"But the majority of the population simply wants to be left out of the conflict," he said.

As a result, large numbers of Palestinians have been forced from their homes in Syria, with what Grandi calls "limited flight options."

The neighboring country, Jordan, has refused to receive any more Palestinian refugees, after taking in about 5,000 from Syria, already hosting around 2 million from before the conflict.

"The only way really open for the Palestinian refugees who want to escape out of Syria because of security concerns, has been Lebanon, the place where life for Palestinian refugees is already very difficult," he said.

Grandi estimated that about half of the Palestinian refugees in Syria have been displaced from their homes by the conflict.

The sensitivities surrounding both the Palestinian refugees' presence in Syria and their movements to neighboring countries, makes them "a very vulnerable group in Syria and also a vulnerable group in the region," he said.