Yemen's Iran-backed Huthi rebels have detained more than a dozen aid workers, including 11 United Nations staff, in an apparently coordinated crackdown, the Yemeni government, aid groups and the UN said Friday.

The abductions underline the perilous task facing aid workers in Yemen, whose long-running civil war has precipitated one of the world's worst humanitarian crises.

"Huthi de facto authorities have detained 11 United Nations national personnel working in Yemen," UN spokesperson Stephane Dujarric said.

"We're pursuing all available channels to secure the safe and unconditional release of all of them as rapidly as possible."