Rio's top security official vowed Thursday to review security for the Olympic torch after rioting protesters blocked the relay ceremony and apparently extinguished the flame.

The violent clashes late Wednesday in Angra dos Reis, a coastal resort south of Rio, cast a shadow over final preparations for South America's first Olympics, which start August 5.

In another worry for organizers, Rio metro employees threatened Thursday to go on strike on the eve of the Games if they do not get a 9.83 percent salary raise, raising the possibility of transport chaos for some 500,000 tourists expected to attend.

Rio de Janeiro state security secretary Jose Mariano Beltrame said that policing during the torch relay -- which will have visited more than 300 Brazilian cities by the time of the opening ceremony in Rio's Maracana stadium -- needs improving.

"There has never been a problem," he was quoted as saying by G1 news site. "Yesterday there was one. This needs to be reevaluated and we will be paying more attention to this question."

"Extinguishing the torch is a crime," he warned.

- Tear gas -

The crowd, protesting a lack of public transport and the late payment of salaries by the nearly bankrupt Rio state, attacked the procession in Angra dos Reis before being driven off by police using tear gas and rubber bullets.

In footage of the clashes shared online and on Globo television, someone can be heard shouting triumphantly: "The torch has been put out!" as the torch bearer, carrying an unlit torch, is hustled into the safety of a bus.

The Rio organizing committee said in a statement that the torch relay "had to be temporarily interrupted."

However, "out of consideration to the inhabitants of the city who wanted to attend the relay," it was restarted at the next stage "after an evaluation by the security team."

Organizers portray the torch's nationwide journey as a chance to ignite public enthusiasm for the Olympics.

But repeated security incidents have turned the torch into a symbol of organizational glitches and social discontent.

Highlight reels of torch mishaps have gone viral online, including several attempts to extinguish the flame, runners falling over, a police motorbike crashing into the parade, a man attempting to seize the torch, and political protests.

In June, a rare, captive jaguar -- the same animal chosen as Brazil's Olympic mascot -- was shot dead after escaping handlers at a torch ceremony.

- Athletes arrive, controversies mount -

There was better news for Rio organizers in the arrival overnight of Jamaican sprinting superstar Usain Bolt, who hopes to defend his multiple gold medals.

Wearing a black tracksuit with white stripes, sunglasses and headphones, Bolt was in a hurry to leave the airport. "I didn't sleep on the flight," he told a welcoming committee of journalists and officials.

A more controversial set of arrivals were expected later in the day, with some 70 Russian athletes due to arrive in the early evening, their team slashed by bans in a scandal over state-sponsored doping.

Rio organizers were also still racing to complete emergency repairs to the athletes' Village, where some 19,000 team members will live.

Half of the buildings had problems ranging from blocked toilets to faulty wiring when teams began moving in over the weekend.

Although these glitches were expected to be ironed out by the end of Thursday, new controversy was brewing over allegations by government labor inspectors that the approximately 600 workers are being made to work nearly around the clock without legal contracts.

- 'Terrorism' charges? -

Meanwhile, officials said that a Brazilian man was arrested at his home in Nova Iguacu, in Rio de Janeiro state, on terrorism charges. However, no details of the allegations were given.

The justice department said the indictment against Chaer Kalaun, 28, a Brazilian of Lebanese descent, was sealed, but had been filed under anti-terrorism laws.

His lawyer, Edson Ferreira, said the allegations lacked substance.

"There's nothing more than suspicions that he put posts on Facebook," the lawyer said.

"He did not pledge allegiance, he was not recruiting, or bringing people or collaborating or encouraging any projects of the Islamic State," he said.

Ferreira said his client is a Muslim and lived in Lebanon when he was an adolescent.

Unconfirmed Brazilian media reports said police suspect Kalaun of recruiting for extremist organizations in Brazil. He was also arrested during the 2014 World Cup on charges of illegal firearms possession.

The arrest came a week after 12 other Brazilian men were arrested for allegedly trying to form a terrorism cell. Officials downplayed the seriousness of the group, calling them "amateur" and "disorganized."

Source: AFP