A powerful explosion occurred outside the headquarters of the Lebanese Blom Bank in the western part of the Lebanese capital Beirut late on Sunday, causing damage to the building, security sources and witnesses said.

The sound of ambulance sirens was heard in the area near the busy shopping district of Hamra Street.

The interior minister told Reuters that the headquarters of Lebanon's Blom Bank was the target of the bomb.

In a statement to Lebanon's news agency LBCI, Lebanon's Interior Minister Nohad Machnouk said that no casualties reported the explosion in Hamra. 

The Lebanese Red Cross said two people received minor injuries, the National News Agency reported.

Smoke rose from the Verdun area of Beirut after the blast. Local television showed footage of a damaged building and said shattered glass had fallen to the ground from several storeys up.

A security source said the bomb had contained 2 kg (4 lb) of explosives.

"Politically it is clear that target was Blom Bank only," he said, adding that the attack had nothing to do with Islamic State (IS) group, which has mounted suicide bombings in Beirut. Machnouk said initial reports indicated there had been no fatalities.

The last bomb attack to hit the Lebanese capital killed more than 40 people in the southern suburbs, an area where the Shia Muslim Hezbollah group is dominant. The bombing was claimed by the Sunni IS group.