The World Health Organization says several hospitals in Taiz have had to stop parts of their medical services. The Yemeni city has lived under a tight siege imposed by the Houthi militia for years, and the pressure on supplies keeps getting worse. In a statement, the UN health agency warned that further interruption of essential services would put thousands of patients in danger. Newborns and people with kidney failure who need regular dialysis are among the groups most at risk. The statement pinned the immediate problem on an acute shortage of fuel and oxygen, without which hospitals cannot run generators or keep patients breathing. Fuel crises in Yemen have repeatedly knocked out power for incubators, operating theatres and medicine storage. Health workers in Taiz have long demanded safe corridors so that fuel and medical shipments can reach the city. Negotiations over humanitarian access have dragged on without a lasting solution.