RIO DE JANEIRO - A pile of rubble is all that's left of this section of the new cycling lane that skirted the Atlantic coast of Rio de Janeiro.

Witnesses say several people and a bus were on it at the time of the collapse, taking advantage of its breath-taking views.

"I saw five people on the bridge. Just as I passed, I turned to look back and saw them get swept away," said witness Damian Piero.

Fire officials say at least two people were killed.

The 50-metre long section that collapsed was part of a 3 kilometre cycling lane opened in January, as part of a project to spruce up the city for the Olympic Games that begin August 5th.

The collapse happened just hours after the Olympic torch was lit in Greece to begin the countdown to the games.

Rio will become the first South American city ever to host the Olympics, but is struggling with its biggest recession in almost a century and a political crisis that could lead to the impeachment of the president.