United Nations Secretary General Ban Ki-moon announced on Wednesday that Valerie Amos would stepped down as the Under-Secretary-General for Humanitarian Affairs and Emergency Relief Coordinator.

Without giving specific reasons for Amos quitting that role, Ban said the former British cabinet minister would leave her post in the coming months.

Amos (pictured above) has served as the UN's aid chief since August 2010, and has overseen aid operations in Syria, as well as the Central African Republic, Iraq and South Sudan.

Her departure comes as the UN struggles to cope with a record 50 million displaced people.

"I would like to express my utmost gratitude for her outstanding service to the United Nations, the humanitarian community and people in need," Ban said in a statement.

Aid for Syria urgent

The announcement came a day after Amos reported to the Security council on efforts to provide humanitarian aid to civilians in Syria, where a bitter civil war has raged for almost four years.

Amos appealed for there to be more cross-border deliveries and urged Security Council members to push Damascus and other parties to find a political solution.

"I hope, for the sake of the people of Syria, that one is found soon," she told them.

"This is the largest number of people displaced from conflict in the world," she said, referring to the 7.6 million people displaced inside Syria and 3.2 million others who have fled the war-torn country.

Former British cabinet minister

Born in Guyana, Amos served as Britain's Africa minister in the former government of ex-prime minister Tony Blair and was also the British high commissioner to Australia.

Amos served as Britain's Secretary of State for International Development between 2003 and 2007, after her predecessor Clare Short stood down in protest over Britain's role in the Iraq War.

rc/ipj (AFP, AP, dpa, Reuters)