The visiting head of the International Olympic Committee (IOC) is "confident about Brazil's security plans for the Rio 2016 Olympic Games," the Agencia Brasil news agency reported on Saturday.

IOC Executive Director Christophe Dubi spoke to reporters in Rio on Friday, describing the security plans as "robust," and commending the level of cooperation between Brazilian security forces and foreign intelligence services, the agency said.

Dubi said he and others were presented two months ago with the security plans and security groups involved, "and we saw confidence in all those participants."

The plans have since been bolstered even further, following the recent terror attack in the southern French resort of Nice.

"The world we live in has changed. Terrorism is no more prevalent in one country than another and I'm afraid that's a factor we have to deal with," the agency cited Dubi as saying.

Also on Saturday, the agency reported police arrested an eleventh suspect in an alleged "amateurish" Brazilian plot to launch terror attacks during the games.

The suspect turned himself in on Friday in the state of Mato Grosso do Sul, which borders Bolivia to the south, according to the agency.

Police issued a total of 12 arrest warrants following a tip from foreign intelligence sources. Those arrested are being kept at a maximum security federal prison in Mato Grosso.