Three swimmers died and 17 others were seriously injured Saturday when a freak wave struck a popular beach in South Africa’s southeastern city of Durban, the emergency services said.

“There was a freak wave that washed some people to sea, three have drowned and 17 people have been taken to hospital,” Robert McKenzie, spokesman of the KwaZulu-Natal provincial first responders services told AFP.

He said one of the dead was a child around 7 or 8 years old, while those injured are “in serious or critical condition.”

The incident occurred around 5 p.m. (1500 GMT) at the Bay of Plenty, one of the popular beaches in South Africa’s third-largest city.

The emergency services said that they were afraid the toll would rise after the “uncommon” event.

Durban has gradually been re-opening its beaches after they were shut due to high levels of E. coli coming from the city’s sewer system, which was badly damaged by deadly floods earlier this year.

The floods, the worst in living memory, killed more than 400 people in April.

Source: Voice of America