The United States has ordered some of its diplomats to leave Yemen amid continuing sectarian unrest in the country.

However, the US State Department confirmed that the US embassy is to stay open in the Yemeni capital, Sana'a.

"Today, the Department of State ordered a temporary reduction in the number of U.S. government personnel in Yemen," the department said in a statement. "We are taking this step out of an abundance of caution and in response to recent political developments and the changing, unpredictable security situation in Yemen."

A US travel warning for American citizens said that the decision was taken "due to the continued civil unrest and the potential for military escalation."

Fighting between rebels and Islamist militias in Sana'a has pushed international airlines to suspend their flights to the Yemeni capital, authorities confirmed last week.

The armed Shia rebels, known as Houthis, are battling the main Sunni Islamist party, Islah, in the Middle Eastern country.