Police carry out controlled explosion on bag left near Olympics cycling finish line

A bomb squad is investigating after an apparent blast shook the area near the finish line of the men's cycling road race at the Rio Olympics.

Reporters could hear a loud boom on the press tribune and felt the ground shake as the cyclists had about 70 kilometres to go Saturday.

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Officials expect the bag may have belonged to a homeless man, but protocol requires any unattended objects be destroyed,a spokeswomanfor the public security department said.

The controlled blast occurred at 1:45 p.m.local time, she said.

A half dozen military police were cordoning off the area. No one was immediately evacuated, and it did not appear that anyone was injured. The race was continuing and had not been rerouted.

There is heavy security all over the city amid concerns about safety as the Olympics begin.