Beirut, Oct 10 (IANS): At least four people were killed and 20 others injured after a fuel tank exploded in a densely populated area of Lebanon's capital city of Beirut, officials said.

The incident took place on Friday night in the city's Tariq-al-Jdide district after the tank caught fire, the BBC reported.

While rescue efforts were ongoing, the cause of the blast was yet to be determined.

Following the blast, firefighters used ladders to scale the outside of apartment buildings to rescue residents from their balconies.

Friday's incident comes as the country was still struggling to recover from the August 4 Port of Beirut explosion and also amid the worst economic crisis.

The explosions, caused by 2,750 tonnes of ammonium nitrate detonating at a warehouse in the port, killed around 190 people, wounded 6,000 others and led to at least 300,000 being homeless.

The blasts caused damages estimated to be worth $15 billion, according to official figures.

Around 45,744 residential units were destroyed by the explosions and the damage was assessed by 250 teams of 1,000 army members and 500 civil engineers.

Experts have said that this was one of the biggest non-nuclear explosions in history.