Yemen's Houthi rebels have raided United Nations offices and detained several people, officials have said.
The group has tightened security across the capital, Sanaa, after their prime minister was killed in an Israeli strike on Thursday.
Sunday's raids were the latest in a long-running Houthi crackdown against the UN and other international organisations working in rebel-held areas of Yemen.
The offices of the UN's food, health and children's agencies were raided on Sunday, according to officials.
Ammar Ammar, a spokesperson for UNICEF, said a number of the agency's staffers were detained, and the agency was seeking more information from the Houthis.
Media reports have suggested that 11 UN workers were detained.
The Houthis have controlled much of northwestern Yemen since 2014 after forcing out the internationally recognised government and starting a civil war.
They are backed by Iran and have conducted repeated strikes on shipping in the Red Sea and Israel.
Read more from Sky News:
A diary of daily life in Gaza
China and India discuss disputed border at key summit
Sunday's events come after rebel prime minister Ahmed al Rahawi and a number of other ministers were killed on Thursday, according to the Houthis.
The Israel Defence Forces (IDF) said on Friday it had "carried out a significant strike against strategic targets of the Houthi terror regime in Yemen".