An explosion at a petrol station in Ghana's capital Accra has killed as many as 90 people, many of whom had sought shelter there from torrential rain on the night of 3 June, the fire brigade said on Thursday (4 June).

The blast was caused by a fire that erupted at a nearby lorry terminal then spread to the petrol station and other buildings, said fire brigade spokesman Prince Billy Anaglate.

"It was raining last night and people took shelter at the filling station. And as they were there, because that is a filling station, it kept raining so there was still running water that was rising up. And, because it is a filling station there were a lot of fuel particles around it and it got contaminated with the water and then those that are not mixable with the water will definitely float. So, they were floating on the surface of the water - but it's running water, so it was able to run from the filling station to a distance where there was a naked fire and it picked the fire from there," Anaglate said.

He said the fire ripped through the filling station, operated by GOIL, shattering windows and walls and reducing the station to rubble.

"Actually we were called here last night [to the] fire at the GOIL filling station. We got there [and] we realised that the GOIL filling station and some adjoining structures were on fire. So we decided to rescue people who were trapped at the residential apartment close to the filling station. We had 10 people that we rescued. Though they received various degrees of burns, we were able to send them to the hospital. And then we continued to fight the fire. It was after fighting the fire that we saw they were lots of dead bodies scattered at the filling station and then we began to retrieve those dead bodies from the filling station," Anaglate said.

Firefighters battled the blaze into the early hours while police and soldiers joined emergency crews helping rescue people trapped in the wreckage, Accra Mayor Oko Vanderpuije said.

Charred corpses and wreckage of about a dozen cars and mini buses littered the forecourt of the station, where security forces kept an anxious crowd behind a police cordon.

A team of rescuers wearing face masks and gloves went in to the filling station with stretchers to remove the remaining bodies, all of which were unrecognisable. Initial signs suggested the fire started by accident, Anaglate said.

Floods from several hours of heavy downpour submerged buildings and vehicles across Accra on Wednesday.

President John Mahama, who visited the area, said he was heartbroken by the heavy loss of lives and damage.

He blamed the floods partly on people building homes and businesses on waterways, blocking the city's drainage systems. Ghana's meteorological service there could be more rains on Thursday.