Official says at least 17 people were hospitalized and in critical condition following a huge wave at Durban’s Bay of Plenty.

A freak wave has killed three swimmers and injured many others at a popular beach in South Africa’s southeastern city of Durban, according to officials.

Robert Mckenzie, a spokesman for KwaZulu-Natal Emergency Medical Services, said the wave on Saturday washed swimmers at the Bay of Plenty out to sea, drowning at least three of them.

At least 17 others were injured and were “in serious or critical condition”, he added.

The incident occurred at approximately 5.00 pm local time (15:00 GMT) on Saturday, according to a statement from the eThekwini municipality.

The office said 35 lifeguards were involved in the “mass rescue effort” and that paramedics attended to more than 100 people caught in the incident.

The dead included a teenager, it said.

The incident took place as Durban has gradually been reopening its beaches after closure due to high levels of E. coli bacteria coming from the city’s sewer system, which was badly damaged by deadly floods earlier in the year.

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

Durban’s beaches are also preparing for an influx of visitors over the coming festive holidays, according to local media outlets.