SYDNEY — Two men and two women died today after a river rapids ride malfunctioned at Dreamworld, a park on Queensland state’s east coast, Queensland police officer Tod Reid said.

The Thunder River Rapids ride whisks people in circular rafts along a fast-moving, man-made river. A malfunction caused two people to be ejected from their raft, while two others were caught inside the ride, said Gavin Fuller, an officer with the Queensland Ambulance Service.

Park staffers administered first aid to the victims, but their injuries proved fatal, Fuller said.

The victims were in their 30s and early 40s, he said.

Reid said he was not aware of any previous problems with the ride.

Police were interviewing witnesses and reviewing closed-circuit television footage of the incident while crews worked to remove the bodies from the scene, he said.

Dreamworld CEO Craig Davidson said the park was working with police to try to determine what went wrong. “We are deeply shocked and saddened by this, and our hearts and our thoughts go out to the families involved and to their loved ones,” Davidson said.

The park was closed following the accident and was expected to remain closed Wednesday.

A witness, Lia Capes, told the Australian Broadcasting Corp. that she was just about to go on the ride when she saw people running out, crying.

“I was speaking to one of the guys and he said it was the raft or the boat thing in front of him, the whole thing flipped and everyone was screaming,” Capes said.

Thunder River is considered one of Dreamworld’s tamer, family-friendly rides, and is open to children as young as 2.

In April, the park’s Rocky Hollow Log Ride was temporarily shut down after a man fell from the ride.