After briefing the UN Security Council on the crisis in the rebel-held town near Damascus, he warned that those people could die.

Earlier, an aid convoy brought food to 40,000 town residents who have been under government siege for six months.

The UN says it has received credible reports of people dying of starvation.

Simultaneously, aid lorries entered two towns besieged by rebel forces in the northern province of Idlib under a deal between the warring parties.

The situation in Foah and Kefraya is also said to be extremely dire, with an estimated 20,000 people trapped there since March.

The arrival of the aid was delayed until both sets of lorries were ready to enter the towns.

In total, some 44 lorries operated by the UN, the International Committee of the Red Cross (ICRC), the Syrian Red Crescent and the World Food Programme (WFP) reached Madaya from Damascus on Monday.

-BBC