The prisoner swap deal was seen as a breakthrough during 2018 peace talks in Sweden.

A report by the World Food Program, the U.N. Children's Fund and the Food and Agriculture Organization said the number of people facing high levels of acute food insecurity is expected to increase from 2 million to 3.2 million in the country's south.

Patrick Cammaert's convoy had come under fire while visiting an area under Saudi-led coalition control.