Thousands of people may have starved to death in Syria's besieged zones, the United Nations human rights chief said on Monday, according to ABC News.

Zeid Ra'ad al Hussein said some of the estimated half a million people trapped in besieged towns and villages had been cut off for years.

"The deliberate starvation of people is unequivocally forbidden as a weapon of warfare. By extension, so are sieges, which deprive civilians of essential goods such as food," he said.

Speaking as the UN and partner organizations get ready to deliver life-saving aid to about 154,000 besieged Syrians in the next five days, Zeid warned the situation could be even worse than first imagined. 

As many as 480,000 people were currently trapped in Syria's besieged towns, he added.

Source: MENA