Syrians, fleeing the violence from the Syrian town of Qara, are seen inside a bus at the Lebanese border town of Arsal, in the eastern Bekaa Valley Nov 18, 2013. Hundreds of Syrians queued in the bleak winter rain of a Lebanese border town on Monday, seeking refuge from a Syrian army attack which could herald a wider offensive north of Damascus.[Photo/Agencies]

UNITED NATIONS -- Some 9.3 million Syrian people need humanitarian assistance, but continued fighting has constrained the aid workers, a UN spokesperson said Thursday.

"Humanitarian organizations are providing assistance to millions of people in Syria but insecurity continues to threaten their lives and their ability to reach people in need," said Fahran Haq at a regular briefing at the UN headquarters.  

Of the estimated 9.3 million people in need, 6.5 million people are displaced Syrians, said Haq, citing the UN Office for the Coordination of Humanitarian Affairs (OCHA).

On the development of vaccination campaign in the war-torn country, Haq said that humanitarian partners have vaccinated 1.4 million children against polio and another 473,000 children against measles so far, though they face access constraints in several parts of the country.

The World Food Programme said due to increasing insecurity, humanitarian convoys sent life-saving assistance to over 312,000 people in hard-to-reach areas in the past two weeks, compared with more than 3.4 million people in October.

The continued conflict between the Syrian government and opposition groups seeking to oust President Bashar Al-Assad, which began in March 2011, have killed more than 100,000 people and forced millions to flee their homes within Syria and into neighboring countries.