The staff were abducted on Friday in Abyan governorate, Russell Geekie, a spokesperson for the top UN official in Yemen, said on Sunday.
“The United Nations is in close contact with the authorities to secure their release,” Geekie added.
An official at the UN office in Aden told Reuters that four of those seized were Yemeni nationals.
Saudi Arabia and its allies launched a war against the Arab world’s most impoverished nation in March 2015. The war has been seeking to restore power in Yemen to Riyadh’s favorite officials.
The death toll of the war, now in its seventh year, will reach an estimated 377,000 by the end of 2021, according to a recent report from the UN’s Development Programme.
The fighting has seen some 80 percent of the population, or 24 million people, relying on aid and assistance, including 14.3 million who are in acute need.