UNITED NATIONS, Dec. 13 (Xinhua) -- Looting and lack of staff and medicine are forcing some healthcare facilities to close in Syria amid the fluid security situation, UN humanitarians said on Friday.

The UN Office for the Coordination of Humanitarian Affairs (OCHA) said the United Nations and its partners continue to support the relief response, resuming activities as security permits.

In northeast Syria, health partners activated more than 20 mobile medical units to handle critical cases and provide primary consultations, OCHA said.

In the northwest, 30 mobile medical teams provided basic healthcare, vaccinations and maternal care, supported displaced people, and delivered aid including food, tents, winter clothes, hygiene kits and cash.

However, the humanitarians said more support is needed to reach more people and support host communities.

The UN Refugee Agency (UNHCR) reported that thousands of Syrian refugees have started returning to the country from Lebanon through the Masnaa border point and other border crossings, going back to Idlib, rural Damascus, Damascus, Daraa, Aleppo, and other locations. At the same time, some Syrians have fled into Lebanon.

Refugees were also reported returning from Türkiye through the Bab al-Hawa and Bab al-Salam border crossings to northwest Syria.

During 14 years of Syrian conflict and crisis, more than 13 million Syrians have been forced from their homes, according to UNHCR. It has not yet provided official numbers on returnees or the new refugees.

"One of the main challenges is that there are no immigration authorities on the Syrian side (of the border)," the UNHCR representative in Syria, Gonzalo Vargas Llosa, told reporters in a telebriefing.

"The immigration officials, who were operating there during the previous regime, all left their positions and the new transitional authorities have not been able yet to establish immigration procedures, which creates, of course, some challenges and difficulties," he said.

The refugee agency also reported that in the past 72 hours, some of their activities in more secure areas were resumed through local partners. The agency said it supported 114 community centers in Syria, providing services to those internally displaced or returning. ■