Controlled explosion in Rio road race
Members of the Brazillian bomb squad carry out a controlled explosion of a bag near the finish line of the Men's Road Race on Day 1 of the Rio 2016 Olympic Games at the Fort Copacabana on August 6, 2016 in Rio de Janeiro, BrazilAFP/Getty

A bomb squad carried out a controlled explosion on an unattended bag at the finish line of the Olympic men's road race in Rio. Several police cars arrived at the scene after reports of a suspicious package.

The backpack was destroyed while the riders in the 237.5km race were on a different part of the course. It's thought the bag belonged to a homeless man.

Spectators on the ground reported a large blast during the race, while TV viewers took to social media after hearing an explosion during coverage of the Games.

A Rio 2016 spokesman confirmed: "The security services found a suspicious package close to the cycle road race finish line in Copacabana and as a precaution decided to perform a controlled explosion. There is no impact to the race, which is ongoing."

Thousands of spectators lined the racetrack to watch the 144 cyclists, including Team GB's Chris Froome, Portugal's Rui Costa, and Spaniard Alejandro Valverde, in the final. Great Britain missed out on claiming their first medal of the Rio 2016 Olympic Games in the men's road race as Greg van Avermaet of Belgium sprinted to victory.

Meanwhile, the Rio Olympics has been beset by problems from the outset, including security issues and crime. Earlier there were reports that a military bullet had been shot through the roof of the equestrian, Sky News reports.

And after Friday's opening ceremony, spectators were confronted by the sight of a man who had been shot dead near the Maracana Stadium. Eyewitnesses reported hearing multiple shots as the shooter fled the scene.

Amid heightened security fears, Brazil has deployed around 85,000 police and military during the Olympic period.