However, his lawyers can argue for special conditions given his age and health. Typically courts in Brazil agree to house arrest or allow foreigners to return home.

Hickey has temporarily stepped down as an executive board member of the International Olympic Committee, as president of the European Olympic Committee and as vice-president of the Association of National Olympic Committees.

The OCI said Hickey, its president, was stepping aside from all his Olympic functions until the matter was fully resolved, and was being replaced by William O'Brien.

IOC spokesman Mark Adams said the allegations concerned 1,000 tickets out of a total of 6.5 million that were made available for the Rio games.

Police have not questioned other officials of the IOC, which is ready to give any assistance to Brazilian authorities, he said. "We have full confidence in the system. Everybody is innocent until proven guilty," Adams added.

Police said the three PRO10 executives did not travel to the country for the Games and were considered "fugitives".

PRO10 says on its website that it is the Irish authorised ticket reseller for the Games. It said in a statement that it had always acted properly and had cooperated fully with Brazilian authorities.

Hickey is a former judoka and is honorary life president of the Irish Judo Federation. He has been head of the OCI since 1989. In 2015, he led the first European Games organised by the EOC in Baku, Azerbaijan.