UN urges Saudi coalition to end 'catastrophic' Yemen aid blockade
"There were no flight clearances granted to our flights today," UN spokesman Farhan Haq said on Monday. "We expected to have two flights going and those are on hold for now."
More than 10,000 people have been killed since a Saudi-led coalition intervened in Yemen in 2015 to support President Abedrabbo Mansour Hadi against the Houthis.
Another 2,100 people have died of cholera since April as hospitals struggle to secure basic supplies amid blockades on ports and the country's main international airport.
Last month, the United Nations put the Saudi coalition on its blacklist for killing and maiming 683 children during the conflict in 2016 and for carrying out 38 verified attacks on schools and hospitals.