Police used stun grenades and tear gas to clear protesters in the path of the Olympic torch in a poor suburb of Rio de Janeiro on Wednesday, two days before South America’s first Olympic Games open under tight security.

Olympic Brazilian sailors earlier delivered the torch to the host city’s mayor after crossing Guanabara Bay near the end of a 20,000km (12,400-mile) journey through one of the world’s largest and most diverse countries.

The flame landed at 9.15am local time while a few kilometres away 450 heavily armed police battled drug traffickers to carry out dozens of arrest orders in the Alemao slum, an area near the international airport and close to the main road to Olympic venues.

Armed soldiers stood patrol on highways and on many corners throughout the city.

Police said anti-government protesters in Duque de Caixas, on Rio’s north side, threw rocks and blocked the torch’s path. Police dispersed them with pepper spray and rubber bullets.

Three people were injured by rubber bullets, including a 10-year-old girl, local media reported.

The clash, which came a day after anti-torch protests in nearby towns and amid several days of gang violence in northern Brazil, underscored social tension in the massive country.

The world’s largest sporting event comes to Brazil in the midst of the country’s worst recession in at least a quarter of a century and an impeachment trial of a suspended president. Many residents struggling with the dire economy question the wisdom of hosting the Olympics, a bid Brazil won in 2009 while the economy was booming.

Some 85,000 police, soldiers and security personnel are being deployed in Rio, more than double the amount in London in 2012, to deter both violent street crime and the threat of attacks by extremists.

Residents have faced hours of traffic jams in recent days as new express bus lanes ferrying athletes and visitors to sport venues take up highway space, leading Mayor Eduardo Paes to declare Thursday the fourth city holiday of the Games.

After picking up the torch at a local naval academy, a grinning Paes took it on its first laps through the streets of downtown Rio. A few protesters cropped up in the mostly celebratory crowd, which cheered to the pulse of drums and samba music.

The Rio organising committee said 1.3m tickets remained unsold on Wednesday, though nearly half of those tickets were for soccer matches held in other cities.

Reuters in Rio de Janeiro