The UN reports that the Syrian government has agreed to allow aid into the besieged rebel-held village of Madaya.
The aid is to help residents of Madaya, who are starving to death. The UN humanitarian co-ordinator said it was planning to deliver humanitarian assistance "in the coming days".
Aid agencies say conditions in Madaya, near Damascus, are "extremely dire".
The UN said it also had government permission for to send aid to besieged rebel towns like Kefraya and Foah in the north.
Up to 4.5 million people in Syria live in hard-to-reach areas, including nearly 400,000 people in 15 besieged locations who do not have access to the life-saving aid they urgently need.
Madaya, which is about 25km (15 miles) north-west of Damascus and 11km from the border with Lebanon, has been besieged since early July by government forces and their allies in Lebanon's Shia Islamist Hezbollah movement.
The UN said it had received credible reports of people dying from starvation and being killed while trying to leave. On 5 January, a 53 year-old man reportedly died of starvation while his family of five continues to suffer from severe malnutrition, it said.