Part of an elevated bike lane built ahead of the Olympic Games collapsed on Thursday, killing at least two people who were on it when cement gave way and crashed onto the beach below.

An Associated Press photographer at the scene saw two dead bodies laid out on the beach. A fire official told the AP by phone that three people were affected by the accident but couldn't immediately provide details on their status and it wasn't clear if they included the two who died.

It wasn't immediately clear why the lane had collapsed.

Ambulances were dispatched to the scene and helicopters hovered over the beach.

Rio de Janeiro is hosting the Summer Games beginning in August and the bike lane was among the projects built in preparation. While no Olympic event will be held on the path, the collapse will likely add to worries about the country's readiness to host the Games.

The bike path runs several miles (kilometers) through southern parts of the city, connecting the tony beachfront neighborhoods of Leblon and Sao Conrado. It snakes along sheer cliffs tens of meters above the surface of the ocean.

Since its January inauguration, the path has earned kudos for its spectacular views. But detractors complained it was dangerous, saying the narrowness of the path made cyclists prime targets for mugging. In the weeks after it was opened, local newspapers also featured photos of its speedy deterioration, showing missing handrails and rusting metal parts.

Construction is underway to extend the bike path westward to the Barra da Tijuca neighborhood that is one of the Olympic hubs.

The accident comes on the same day that a flame for South America's first Olympics was lit in Greece, heralding the start of a 15-week journey that will culminate with the August 5 opening ceremony in Rio de Janeiro.

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Jenny Barchfield and Steve Wade in Rio de Janeiro contributed to this report.