The billionaire financier George Soros is pledging $1m for humanitarian efforts in war-ravaged Syria.

Soros announced the pledge to the International Rescue Committee on Wednesday night after receiving its Freedom award in recognition of his lifelong support for human rights and an open society.

Soros said people were starving and would soon be freezing in Syria as winter arrived, and malnutrition among children was increasing.

"This situation has arisen because both the government and the rebels use the denial of humanitarian aid as a tool of war," Soros said.

While prospects for a political settlement have improved following a US-Russian agreement, he said, "conditions for the civilian population are deteriorating because both sides continue to interfere with aid delivery in order to improve their negotiating positions in the coming peace talks".