The Department of State has issued a travel advisory for Yemen, warning U.S. citizens of the high security threat level in the Middle Eastern country due to terrorist activities and the ongoing civil unrest.

The Department of State said Americans currently in Yemen should consider departing, as evacuation options are limited.

Should a crisis occur, evacuation options from Yemen would be extremely limited due to the lack of infrastructure, geographic constraints, and limitations over the ability of U.S. Embassy to assist U.S. citizens in the event of a crisis in Yemen, the travel warning said.

Piracy in the Red Sea, Gulf of Aden and Indian Ocean is also a security threat to maritime activities in the region. Terrorist organizations continue to be active in Yemen, including Al-Qaeda in the Arabian Peninsula (AQAP), the Department of State said in a statement on Sunday..

According to media sources, suspected Al-Qaeda men shot down six Yemeni soldiers in three separate attacks on Sunday, which has intensified the unrest further.

Since Yemen is a U.S. ally in its war against the Al-Qaeda, U.S. citizens can be possible terror targets.

The U.S. government remained concerned about possible attacks against American citizens, facilities, businesses, and perceived U.S. and Western interests, the Department of State said.