Twelve trucks of humanitarian supplies, the second in a week, entered three besieged Syrian towns Thursday, a member of a relief committee in one of the areas told dpa.
"Six of the 44 trucks which are carrying mainly winter clothes," entered the rebel-held town of Madaya near the capital Damascus, Mazen Burhan told dpa by Skype.
Burhan stressed that the people of Madaya are waiting "anxiously" for the rest of the trucks to enter as they are carrying flour.
"People are standing in the streets waiting more than anything for the flour supply to make bread," Burhan said.
At the same time, six trucks out of 17 entered the government-controlled towns of Foua and Kefraya in north-western Syria, a UN source said.
Earlier Pawl Krzysiek,a spokesman for the International Committee of the Red Cross (ICRC), told dpa that the aid would be delivered simultaneously to the three towns in a joint operation conducted by the UN agencies, the ICRC and the Syrian Red Crescent.
A nutritionist is accompanying the Madaya-bound convoy in order to assess the situation inside the town, which has been under siege by Syrian government forces and fighters from the allied Lebanese Shiite movement Hezbollah.
On Monday, Madaya, which has a population of around 40,000, received its first relief supplies since October.
Reports of starvation in Madaya, a mountain town near the Lebanese border, had triggered a global outcry.
The medical aid group Doctors Without Borders (MSF) says almost 30 people have died in Madaya due to a shortage of food since early December.
The pro-regime Shiite villages of Foua and Kefraya have been besieged by hardline Islamist rebels since April.
The ICRC says some 20,000 people are thought to live there.
The aid deliveries were arranged under a UN-sponsored deal between government and rebel forces.
The United Nations said nearly 400,000 of the 4.5 million people living in what it terms "hard-to-reach" areas in Syria are living under siege.
The intentional starvation of the Syrian people in besieged areas constitutes a war crime, UN Secretary General Ban Ki-moon said Thursday in New York.
"The use of starvation as a weapon of war is a war crime," Ban said.
"All sides – including the Syrian government which has the primary responsibility to protect Syrians - are committing this and other atrocious acts prohibited under international humanitarian law."
Ban called on all international actors to press warring parties in the country to allow unimpeded humanitarian access.
France and Britain called for an emergency meeting of the UN Security Council for Friday to discuss humanitarian access in Syria.
Meanwhile, US Secretary of State John Kerry and his Russian counterpart, Sergei Lavrov, have agreed to meet on January 20 in Zurich for talks to focus on the conflict Syria, among other topics, the Russian Foreign Ministry and US State Department said Thursday.