Restoring aid deliveries to Tigray was a key part of an agreement signed on November 2 to end a two-year war that has killed untold numbers of people and unleashed a humanitarian crisis.

"That peace process has not yet resulted in the kinds of full access, unfettered access and the massive scale-up of medical and health assistance that the people of Tigray need," WHO emergencies chief Michael Ryan told a press conference.

"We've been a long time waiting to get access to these desperate people."

The region was isolated from the world for over a year, and faced severe shortages of medicines and limited access to electricity, banking and communications.

"We are seeing some increase in access, in terms of getting some of our staff in. We've had a small allocation of fuel that will allow us to do some operations, and we're starting to see a small trickle," Ryan said, therefore "a tiny percentage of the need that's there, potentially, we can meet."