A huge gas blast in the Kenyan capital, Nairobi, has killed at least three people and injured nearly 300.

A lorry carrying gas exploded in Embakasi district at about 23:30 (20:30 GMT), "igniting a huge ball of fire", a government spokesperson said.

Housing, businesses and cars were damaged, with video showing a huge blaze raging close to blocks of flats.

The area has been cordoned off and an investigation is under way into the cause of the explosion.

The BBC understands that at least one person has been arrested over the incident.

The government initially said the blast happened at a gas plant where workers were refilling gas cylinders, but the authorities later clarified that a truck had exploded in its parking yard.

The fire that broke out as a result has been contained.

Embakasi police chief Wesley Kimeto said a child was among those who died, adding that the death toll could rise.

Some 271 people were taken to hospital, according to the authorities - including at least 25 children.

Nairobi's Mayor Sakaja Johnson said many of these people had been treated and sent home, but at least 39 have been sent to other facilities with serious or critical injuries.

A further 27 people were treated on site for non-life-threatening injuries.

Its head of disaster operations, Vanant Ndhingila, told the BBC's Newsday programme that a search and rescue operation was under way. They are trying to find out if people are missing or have simply taken shelter elsewhere.

"There is still a search going on of whether there are bodies which have been burnt in various houses," said Embakasi East MP Babu Owino.

The Energy and Petroleum Regulatory Authority (Epra) said in a statement that the gas plant was illegal and that it had rejected three applications for construction permits to build a storage and filling facility at the site.

The fireball from the blast had "spread widely", according to government spokesman Isaac Mwaura, and a flying gas cylinder had hit a clothing and textiles warehouse, burning it down.

"The inferno further damaged several vehicles and commercial properties, including many small and medium sized businesses," he said in a statement.

"Sadly, residential houses in the neighbourhood also caught fire, with a good number of residents still inside, as it was late at night."

About 10 trucks were completely burned inside the compound where the explosion occurred.

One burned vehicle landed on top of a block of flats dozens of metres away, partially destroying the building's front.

Witnesses told the BBC that the explosion sent objects including gas cylinders and a shipping container, flying into the air.

Jackline Karimi said she ran out of the house and lay flat on the tarmac. She suffered burns on her right hand and arm up to the shoulder and to her right leg.

"I saw a woman on fire, but we couldn't help her. Everyone was running," Ms Karimi said.

Another woman who was in a flat near the scene of the blast told the BBC she was trying to trace her friend. "She was pregnant and had a child in the house, which is now completely burned."

Boniface Sifuna told the Reuters news agency he was burnt by an exploding gas canister.

"It exploded right in front of me and the impact knocked me down and the flames engulfed me. I am lucky that I was strong enough to get away."

James Ngoge, who lives across the street from where the blast happened, told the AFP news agency that he was in his house at the time and "heard a huge explosion".

"It felt like it was going to collapse. At first, we didn't even know what was happening, it was like an earthquake.

"I have a business on the road that was completely destroyed."

Government spokesman Mr Mwaura said a command centre had been set up to help co-ordinate rescue operations.

"Kenyans are hereby advised to keep off the cordoned area in order to allow the rescue mission to be carried out [with] minimal disruptions," he added.

With additional reporting by Kathryn Armstrong and Thomas Mackintosh in London