Updated

The U.N. humanitarian chief is urging the Syrian government to give a green light for the United Nations to deliver aid to thousands in need in the war-ravaged country and ensure the safety of aid workers.

Stephen O'Brien said in an interview Friday with The Associated Press that there are "incessant and relentless contacts going on" with the government but so far has received no positive response.

He says the cessation of hostilities is "extremely welcome" and urged Syria's government to allow the U.N. in with supplies to meet humanitarian needs.

O'Brien says the U.N. has the materials and aid workers on the ground.

He adds: "We simply need the assurances and the guarantees of safety in order to have the full access to everybody who has needs."