Brazil arrested 10 people on Thursday suspected of belonging to a poorly organized group supporting Islamic State (IS) and discussing terrorist acts during the next month's Olympic Games in Rio de Janeiro.

The group, described as "absolutely amateur" by Justice Minister Alexandre Moraes, were all Brazilian citizens and in contact via messaging apps such as WhatsApp and Telegram. They did not know each other personally, the minister said.

The arrests came a week after a truck massacre in Nice, France, and amid growing fears of a possible attack when the first Olympics to be held in South America kicks off on Aug. 5. Some 500,000 visitors are expected to travel to Brazil for the Games, many of them from the United States.

Although Brazil has no history of conflict with known militant groups, Moraes said the Games had made the Latin American country a more likely target, particularly because of participation by countries fighting IS.

"Today was the first operation against a supposed terrorist cell in Brazil," he told a news conference. "Brazil was not part of the coalition against IS but, because of the upcoming Olympics and because it will receive many foreigners, Brazil has become a target."

Source: b'Soldiers of the Brazilian Armed Forces stand guard outside the 2016 Rio Olympics Park / Source: Reuters '

Moraes said the individuals detained on Thursday were being monitored because they had accessed websites linked to IS, but the group had "no preparation at all" and was a "disorganized cell". He said that authorities intervened when the group started planning actions including martial-arts training and the purchase of firearms.

While the group did not have direct contact with IS, some members had made "pro forma" declarations of allegiance to the militant Islamist group via social media, the minister said.

A presidential aide said on Thursday that Brazilian police and intelligence services had cooperated with French, German, British, Israeli and U.S. intelligence agencies in the arrests.

Brazil's federal police are monitoring around 100 people for possible links to terrorist groups, mostly in the lawless tri-border region with Paraguay and Argentina, said the aide, requesting anonymity.

"Brazil was really being preemptive in this case," said Scott Stewart, vice president of tactical analysis at Stratfor, a global intelligence and advisory firm. "There are some tactical benefits to arrests like this...You could disrupt anything in the works and it may also give other people pause."

(Feature Image Source: Reuters)