WASHINGTON: The United States has shut down its embassy in Yemen indefinitely and evacuated its staff and their families due to the worsening security conditions in the country, the State Department said Tuesday.

“On February 11, 2015, due to the deteriorating security situation in Sanaa, the Department of State suspended embassy operations and US Embassy Sanaa American staff were relocated out of the country,” a State Department travel warning said.

“All consular services, routine and/or emergency, have been suspended until further notice,” it added.

The Shia Muslim militia that has grabbed power in Sanaa warned Tuesday against any attempts to “destabilise” Yemen as the UN brokered a second day of talks aimed at resolving the crisis.

The country has never managed to achieve stability since longtime president Ali Abdullah Saleh stepped down in early 2012 after a bloody year-long popular uprising.

This includes battling an Al Qaeda insurgency and facing a separatist movement in the formerly independent south.

Matters worsened in September when the Huthi militia, fearful of being marginalised by a proposed new constitution, seized control of the capital and began pushing southward into Sunni areas.

UN envoy Jamal Benomar has warned that Yemen is at a “crossroads”, and has urged political leaders to “take up their responsibilities and achieve consensus” as he battles for a negotiated solution.

The United States has also pressed for progress on that front.

“We reiterate the call of the United Nations Security Council for immediate release of President Hadi, Prime Minister Bahah, and members of the Yemeni cabinet. An inclusive political process cannot resume with members of the country's leadership under house arrest,” State Department spokeswoman Jen Psaki said in a statement.

Earlier Tuesday, US officials said the embassy closure would not affect counterterrorism operations against Al Qaeda’s Yemen branch, which America views as the world's most dangerous branch of the terror group.

British embassy shuts down, evacuates staff

The British Embassy in Yemen's capital closed and evacuated its staff early Wednesday, authorities said.

In a statement, UK Minister for the Middle East Tobias Ellwood also urged British citizens still in Yemen to “leave immediately”.

“The security situation in Yemen has continued to deteriorate over recent days,” Ellwood said. “Regrettably we now judge that our embassy staff and premises are at increased risk.”

Yemen has been in crisis for months, with Shia Huthi rebels besieging the capital and then taking control.

The Huthis, who are traditionally based in northern Yemen bordering Saudi Arabia, swept into Sanaa in September and have seized other territory since. Many link the Houthis to regional Shia power Iran, though the rebels deny they are backed by the Islamic Republic.