The US has condemned the continuing detention of Yemeni staff of its embassy in Sanaa by the Houthi rebels. Dozens of Yemeni citizens and their families have been detained and mistreated by the Iran-aligned Houthis because they worked for the US in a caretaker capacity since the embassy closed in 2015. "The Houthis must immediately release unharmed all Yemeni employees of the United States, vacate the embassy compound, return seized property, and cease their threats," Secretary of State Antony Blinken said on Twitter. The UN Security Council has also condemned the Houthis' intrusion. A statement last week approved by all 15 members of the UN’s most powerful body called for “an immediate withdrawal of all Houthi elements from the premises” and “the immediate and safe release of those still under detention”. The Security Council stressed that the Vienna convention prohibits any intrusion into diplomatic property as well as the “inviolability” and “immunity” of the premises from searches and requisition — and that property and archives of a diplomatic mission that has been temporarily closed “must be respected and protected”. The council’s statement followed a demand on November 17 by the UN for the release of two UN staffers detained earlier this month by the rebels. UN spokesman Stephane Dujarric said last week that UN officials were given assurances by senior Houthi officials that the two men, both Yemenis, would be released. On Thursday, he said that they had still not been freed. The two men, who work for the UN human rights office and Unesco, were detained on November 5 and November 7. Yemen has been engulfed by civil war since 2014, when the Houthis took control of the capital, Sanaa, and much of the northern part of the country, forcing the internationally recognised government to flee to the south, then to Saudi Arabia. A Saudi Arabia-led coalition entered the war in March 2015, backed by the US, to try restore President Abdrabu Mansur Hadi to power.