Washington (CNN) U.S. and Brazilian authorities are hunting for a former Guantanamo Bay detainee who has disappeared from Uruguay, as a South American airline issued a warning he may try to use a fake passport to enter Brazil ahead of the Olympic Games there next month. Several senior U.S. officials said 44-year-old Abu Wa'el Dhiab, a Syrian national, went off the radar several weeks ago from Uruguay, where he was resettled in 2014 after being released. Uruguayan officials said he traveled to Brazil, but Brazilian officials told CNN they have no record of Dhiab having legally entered their country. Avianca Brazil Airlines issued an alert warning employees that Dhiab may try to fly using a fake passport, a representative from the airline told CNN. An image of the alert, first published by the Argentine web news portal Infobae, says the information came from Brazil's anti-terrorism police.Concern that he's headed to the OlympicsAirline issues alert he may try to use fake passport
Dhiab's disappearance raises concerns about regional security in the weeks leading up to the 2016 _ in Rio de Janeiro that are due to begin in August.