The U.S. Embassy restricted the movement of its staff in Beirut, Lebanon Wednesday and urged Americans to exercise caution a day after a bomb hit one of its vehicles in the first targeted attack in more than two decades against American diplomats in Lebanon's capital city.

Two Lebanese and a Syrian were killed in the attack, which took place as President Bush was touring the Middle East. An armor-plated U.S. embassy car was damaged, with the car's Lebanese driver, an American theology teacher and 24 others wounded.  The targeted vehicle was apparently one which scouts roads before US diplomats travel them.

The United States has backed anti-Syrian forces in the fractured Lebanese government, which has yet to choose a president following the assassination of Lebanese President Rafik Hariri. A Tuesday farewell reception for the departing U.S. ambassador to Lebanon was cancelled in the wake of the bombing.