(CNN) -- The State Department is warning U.S. citizens against all travel to Sudan and Afghanistan following the recent U.S. military strikes against terrorist targets in those countries.

Citing possible threats to Americans and American interests in both nations, the State Department said U.S. citizens already in Sudan and Afghanistan should depart as soon as they are able to do so safely.

The United Nations has announced plans to withdraw its American employees from Afghanistan.

The State Department said frequent military operations continue in Afghanistan, "sometimes involving intense fighting," and Westerners in the country are vulnerable to politically and criminally motivated attacks and violence, including robbery, kidnapping and hostage-taking. Furthermore, close to 10 million landmines pose a threat to anyone in Afghanistan.

In a separate announcement, the State Department advised Americans in Lesotho to exercise caution and avoid protest venues and large crowds. Maseru, the capital, has recently been the center of unrest. Isolated incidents of political violence have occurred in Maseru and in outlying districts.