Shots were fired near the US embassy in Lebanon late on Wednesday, mission spokesman Jake Nelson has said, with the gunfire coming on the anniversary of the 1984 bombing of the embassy, which killed 24 people.
"At 10.37pm local time, small arms fire was reported in the vicinity of the entrance to the US embassy," Mr Nelson said in a statement carried by Lebanon's state news agency.
"There were no injuries and our facility is safe. We are in close contact with host country law enforcement authorities."
It is not yet known who was behind the gunfire but the incident occurred on the 39th anniversary of the September 20, 1984 car bombing of the relocated US embassy, in which 24 people were killed.
That attack followed another fatal bombing the previous year, on April 18, 1983, when a suicide bomber detonated a van laden with 2,000 pounds of explosives, killing 63.
This year, the US marked the 40th anniversary of that attack, which US officials blamed on the Lebanese militant group Hezbollah.
The 1983 US embassy bombing was what prompted the mission to relocate from central Beirut to the nearby suburb of Awkar.
In recent years there have been no reported attacks on the embassy and any breaches of security around it are rare.
Gunfire is not uncommon in Lebanon, where it is often used to celebrate weddings and graduations.
Lebanon's Say No to Violence Association has condemned "these suspicious actions that endanger Lebanon's security and its international relations with friendly countries as a result of the dangerous actions".
The association's media president Tariq Abu Zeinab called on "the Lebanese authorities to expedite opening an investigation into the shooting".