At least 100 trucks of humanitarian aid were preparing to set off for besieged areas of Syria from Damascus on Wednesday, the Syrian Red Crescent said, in the latest delivery of supplies to trapped residents.

The Syrian government has approved access to seven besieged areas, the United Nations said after crisis talks in Damascus on Tuesday, a week ahead of a planned resumption of peace talks between Syria's warring parties.

The aid convoys would on Wednesday head for Madaya, Zabadani and Mouadamiya al-Sham near Damascus, and to the villages of al-Foua and Kefraya in Idlib province in the northwest, five of the locations named by the United Nations, a spokesman for the Red Crescent said.

Supplies included wheat and high-energy foods. A medical team would enter Kefraya and al-Foua, the spokesman said.

The Syrian Red Crescent was coordinating with the U.N. on the aid deliveries.

The United Nations has demanded unhindered access to all besieged areas of the country, where it says hundreds of thousands of people are trapped by fighting and deliberate blockades by Syria's various warring sides.

Dozens in Madaya have starved to death after months of siege by government forces and their allies.

Insurgents in control of Idlib have in turn surrounded al-Foua and Kefraya, where there have been increasing shortages of food and medical supplies.

In the city of Deir al-Zor in eastern Syria, parts of which are under siege by Islamic State group, unverified reports have said up to 20 people have died of starvation.

Deir al-Zor was one of the seven areas to which the aid convoys were expected to head within the next few days, the United Nations said. The Red Crescent did not mention Deir al-Zor on Wednesday.

Aid was delivered to Madaya, al-Foua and Kefraya last month as part of an agreement between warring sides.

Syria's opposition says it will not negotiate with Damascus until sieges imposed by government forces and their allies have been lifted - one of many issues that led to a suspension of peace talks in Geneva earlier this month.

Talks are scheduled to resume on Feb. 25, but fighting continues unabated throughout the country, where 250,000 people have been killed in five years of war.