Some 175 people have died in a fire at a petrol station in Ghana's capital, Accra, officials say.

The fire on Wednesday night started as people in the city were trying to cope with two days of heavy rain, which has left many homeless and without power.

The flooding hampered rescue efforts and may have led to the fire, the BBC's Sammy Darko reports from Accra.

President John Dramani Mahama has announced three days of national mourning to begin on Monday.

It is thought that people were in the petrol station sheltering from the downpours when the fire broke out, our correspondent says.

President Mahama visited the burnt-out petrol station and described the deaths as "catastrophic" and "almost unprecedented".

He vowed to take tough measures to stop people building on waterways, which appeared to have been a factor in the disaster.

"I think that the time has come for us to remove houses out of water and the public should understand that it is necessary to save everybody else," he said.

Following an emergency meeting of cabinet and security chiefs on how to tackle flooding, the government says it will release £9m ($14m) to help flood victims.

Schools were closed across the capital and children asked to stay at home.

Survivor Yaw Aforve said he was sleeping in his car at the petrol station when he heard the fire. Photo taken from BBC.

Bus conductor Yaw Aforve was sleeping in his vehicle which was parked at the petrol station when the fire started.

He said he jumped into the floodwaters and when he came up for air, the fire burnt his face.

"I was swept away by the water to the other side [of the road]," he added. "I saw so many people screaming and shouting."

The petrol station was totally destroyed by the fire. Photo taken from BBC.

The flooding helped cause the fire, the Ghana fire service said.

The waters "caused the diesel and petrol to flow away from the gas station, and fire from a nearby house led to the explosion", spokesman Billy Anaglate said, the Associated Press news agency reports.

One of those who died in the blaze was a child. Photo taken from BBC

Many homes have been flooded and people have been wandering around in their nightclothes after being forced to leave their beds.

One man told a local radio station that he had put his children on top of a wardrobe to save them from the water coming into his house.

Weather forecasters are saying that more rain is on its way.