Thirteen people have been killed in the east of South Africa after a bridge they were crossing collapsed under heavy rain, a public safety official said Tuesday.

"Several cars were swept away after the bridge collapsed, and 13 people were killed," said Jabu Mabuza a regional spokesman for the department of public safety.

"Police divers are still at the scene to search for more bodies," he added.

Several people were rescued and transferred to hospitals with three still in critical condition.

Torrential rain pounded the area on Monday afternoon, causing the bridge to collapse, but the damage was made invisible by high water levels.

Heavy rains have hit parts of South Africa since Sunday as the rainy season gets underway.