The United States and Britain closed their embassies in Yemen for security reasons Saturday after warning against traveling to this country.
The State Department said the threat to U.S. citizens "remains high due to terrorist activities" and authorized the voluntary departure of non-emergency personnel and eligible family members.
Officials said they were concerned that extremists might carry out attacks against U.S. citizens or interests.
Friday the British government warned its citizens to avoid traveling to the area around Sa'dah, a city 125 miles northwest of San'a where clashes between government troops and supporters of a slain rebel Shiite cleric have killed at least 43 troops and 37 militants since March 28.
Yemen is the ancestral home of al-Qaida leader Osama bin Laden. In 2000, al-Qaida suicide bombers blew a hole in the destroyer USS Cole as it refueled in Yemen's Aden harbor, killing 17 sailors.