RIO DE JANEIRO • The threat of attack by militant Islamists is on the rise in Brazil as the country prepares to host the Olympic Games in Rio de Janeiro in August, the national intelligence agency said on Thursday.

Brazil has long regarded itself an unlikely target of extremists, thanks to its historical standing as a non-aligned, multicultural nation that is free from enemies.

But Counterterrorism Director Luiz Alberto Sallaberry said that the threat had increased in recent months, due to attacks in other countries and a rise in the number of Brazilian nationals suspected of sympathising with Islamic State in Iraq and Syria (ISIS) militants.

He also confirmed that a credible threat to state security had been made last year.

A tweet reading "Brazil, you are our next target", sent in November by Maxime Hauchard, a French national identified as an executioner in ISIS propaganda videos, was genuine, he said.

Mr Sallaberry said his agency had taken several measures to avert a potential attack, including sharing information with foreign security forces and improved training.

But security experts have warned that many Brazilian officials do not realise how big a stage the Olympics is for anyone seeking to sow terror, either through an attack on venues, infrastructure or the athletes and tourists expected to attend.

Brazilian officials, eager to pull off South America's first Olympics after successfully hosting the football World Cup last year, have said previously that they will ensure a safe games starting on Aug 5.

Organisers plan to deploy around 85,000 security personnel for the games, double the number used in London in 2012.

REUTERS