UNITED NATIONS, Nov. 3 (Xinhua) -- United Nations Secretary-General Antonio Guterres on Saturday welcomed a joint aid operation, delivering vital humanitarian assistance to 50,000 people in Syria's Rukban camp.

The UN chief recognized in a statement that while "the long-needed delivery is an important achievement, the overall humanitarian access to this informal desert camp remains wholly inadequate."

As such, he called on all relevant actors "to ensure continued, full, safe, sustained and unimpeded humanitarian access to the tens of thousands of displaced Syrians in this remote area, and to all people in need throughout the country."

"The population at Rukban has not received assistance since January this year, and they are increasingly desperate," UN Emergency Relief Coordinator Mark Lowcock recently told a Security Council meeting on the humanitarian situation in Syria.

"We are delivering food, sanitation and hygiene supplies, nutrition and health assistance, in addition to other core relief items in cooperation with the Syrian Arab Red Crescent," said Ali Al-Za'tari, UN resident and humanitarian coordinator in Syria.

The inter-agency aid operation is expected to take three to four days as it also conducts an emergency vaccination campaign "to protect some 10,000 children against measles, polio and other deadly disease," and undertakes rapid needs assessments.

The delivery was initially scheduled for Oct. 27, but was postponed due to security reasons.

With basic commodity shortages, protection concerns, increasing violence and the death of several children reportedly without access to medical treatment, the overall situation in the camp remains critical.

Rukban camp, which is a cluster of about 10,800 makeshift tents and mud huts in the desert close to the border with Jordan, has been labeled by news reports as "one of the most desperate places in Syria."

The UN urges all parties to allow safe, sustained and unimpeded humanitarian access to all in need in line with their obligations under International Humanitarian Law.

"While this much-needed delivery is an important achievement, a longer-term solution must be found for the many civilians living in Rukban," said Al-Za'tari.