Lebanese security officials said no foreigners were killed.
The explosive device is believed to have been planted in a car that approached an embassy jeep shortly before the blast.
U.S. State Department spokesman Sean McCormack told journalists in Washington that the Lebanese driver of the jeep was slightly injured in the blast, but that there were "no American diplomats or American citizens in the car at the time."
Lebanon has seen around 30 similar bomb attacks in the past three years, mostly aimed against Lebanese politicians and journalists.
Russia's Foreign Ministry condemned the attack.
"We hope that attempts to destabilize and shatter the situation will not prevent the Lebanese from continuing to seek a way out of the crisis by ensuring the soonest possible election of a president," the ministry said in a statement.
