A bomb exploded outside the headquarters of Lebanese Blom Bank in central Beirut on Sunday, causing damage but no fatalities, the interior minister said.
The Lebanese banking sector has been at the centre of an escalating crisis since the United States passed a law requiring banks to take steps to target the finances of the political group Hezbollah.
There was no immediate claim of responsibility.
Lebanon's central bank has pushed its commercial banks to heed the U.S. act, and Blom Bank is one of those that has closed accounts belonging to people suspected of links to Hezbollah. The group had no immediate comment on the blast.
The Lebanese Red Cross said two people had suffered minor injuries in the blast, which took place around 8 p.m. in the Verdun area of Beirut, the National News Agency reported.
Local television showed footage of a damaged building, with one hole in a concrete wall, and said shattered glass had fallen to the ground from several storeys up.
The head of Lebanon's internal security force, Ibrahim Basbous, said the bomb had contained around 15 kg of explosive material and had been placed in a flower bed, the National News Agency said.
Interior Minister Nohad Machnouk said: "Politically it is clear that the target was Blom Bank only."
The last bomb attack to hit the Lebanese capital killed more than 40 people in November in the southern suburbs, an area where Hezbollah is dominant. That bombing was claimed by the IS group.
Finance Minister Ali Hassan Khalil tweeted that the attack had "targeted the stability of the whole of Lebanon".