NEW YORK (REUTERS) - UN humanitarian chief Stephen O'Brien told the UN Security Council on Friday (March 10) the world was facing the "largest humanitarian crisis since the creation of the United Nations" with more than 20 million people facing starvation and famine across four countries.

He said without collective and coordinated global efforts, "people will simply starve to death".

Briefing the Security Council on his recent visit to Yemen, South Sudan, and Somalia, O'Brien said the common factor in those countries was conflict.

He stressed that the international community therefore had the "possibility to prevent and end further misery and suffering" in those countries at risk of famine.

The UN has asked for an injection of funds to Yemen, South Sudan, Somalia and northeast Nigeria - regions in the midst of conflict and on the edge of famine.