Rescue teams in South Africa are searching for survivors after a five-storey building under construction collapsed, killing five people and leaving at least 50 trapped.

Officials in the city of George, Western Cape province, say 24 people have been pulled from the wreckage and taken to hospital.

Some 75 crew were on the site when the building collapsed on Monday afternoon.

The cause of the incident in the coastal city is being investigated.

Emergency services rushed to the scene after the building collapsed at 14:09 local time (12:09 GMT).

Two of the 22 people pulled from the wreckage died of their injuries. Another three deaths were reported later.

"Our thoughts are with the families and all those affected who continue to wait for word of their loved ones," said George Mayor Ald Van Wyk.

More than 100 rescuers with sniffer dogs worked through the night to locate those trapped in the building. Heavy lifting equipment is being used to assist the operation.

Officials said they had been able to establish contact with some of those under the rubble.

Photos have emerged showing a completely flattened construction site, with parts of the building's roof laying atop the rubble.

"I saw one guy was working and then 'boom' and I saw the whole building collapsed... I'm also traumatised. It is very sad," local councillor Theresa Jeyi was quoted as saying by Reuters news agency.