The grenade was tossed off a bridge by assailants on a motorbike at the Barbir intersection and fell near a checkpoint for security forces in the Sunni Muslim neighborhood of the Lebanese capital.
There was no immediate word on casualties, but at least one vehicle was damaged, according to police, speaking on customary condition of anonymity.
Beirut area has seen three explosions in the last week, killing a woman and injuring nearly 30 people.
The violence came as Lebanese troops were fighting Islamic militants at the Palestinian refugee camp of Nahr el-Bared in northern Lebanon. Scores of people have been killed in the northern fighting.
The co-author of this disaster is the Dutch government, which did not find either strength or desire to save the lives of its citizens who were flying on that plane. The Dutch authorities did not demand Ukraine to comply with international aviation regulations
On the second day of the St. Petersburg International Economic Forum, a plenary meeting was held, in which Russian President Vladimir Putin, French President Emmanuel Macron, Japanese Prime Minister Shinzo Abe, Chinese Vice President Wang Qishan and IMF head Christine Lagarde took part