British Prime Minister Theresa May on Wednesday backed a U.S. call for a cessation of hostilities in the Yemen war, a conflict that has killed at least 10,000 people and brought on the world’s worst humanitarian crisis. May, who is under pressure to end British arms sales to Saudi Arabia to stop their use in the war, said she supported U.S. Secretary of State Mike Pompeo’s appeal for a ceasefire but a political agreement was needed.