Lebanon ? A bomb hidden on a Beirut highway hit a U.S. Embassy vehicle Tuesday, killing at least three Lebanese bystanders in the first attack in years targeting American diplomatic interests in the country.

The car’s Lebanese driver and an American at a nearby school were among five people injured.

The blast, just before a farewell reception for the U.S. ambassador in downtown Beirut, came at a time when political tensions are high in Lebanon, with the U.S.-backed government and Syrian-backed opposition deadlocked over choosing a new president.

The U.S. Embassy said it was limiting movement of its personnel as a result of the attack. It also urged Americans in Lebanon to maintain a high level of vigilance, avoid popular gathering spots, and to report suspicious activity to police.

It appeared to be the first time the United States has been targeted in a politically motivated attack in Lebanon since the mid-1980s, when U.S. troops were deployed in the aftermath of Israel’s invasion of the country and a civil war was raging.