Shots were fired Wednesday night near the entrance to the embassy compound in Aukar, a northern suburb of Beirut. No one claimed responsibility for the shooting and the motives behind it were not known.
After the shooting, the Lebanese army launched an investigation, which included analyzing security camera footage from the area.
Lebanon has a long history of attacks against Americans.
Earlier that year, on April 18, 1983, a bombing attack on the U.S. Embassy in Beirut killed 63 people, including at least 17 Americans. Top CIA officials were among those who died. U.S. officials blamed the Iran-backed Lebanese militant group Hezbollah.
After that attack, the embassy was moved from central Beirut to the Christian suburb of Aukar, north of the Lebanese capital.
On Sept. 20, 1984, a suicide bomber struck the embassy compound in Aukar, killing himself and 14 others, prompting the embassy to close.
The United States withdrew all diplomats from Beirut in September 1989 and did not reopen its embassy until 1991.
In 2008, an explosion targeted a U.S. Embassy vehicle in northern Beirut, killing at least three Lebanese who happened to be near the car and wounding its Lebanese driver. An American passerby was also wounded.
In 1976, U.S. Ambassador Francis E. Meloy Jr. and an aide, Robert O. Waring, were abducted and killed in Beirut. In 1984, William Buckley, the CIA station chief in Beirut, was abducted and killed by the Iran-backed Islamic Jihad group.