Hackers briefly disabled three websites belonging to the Brazilian government early on Wednesday in the latest of an international wave of cyber attacks on companies and organizations.

The sites for Brazil's federal government, presidency, and tax collection agency were inaccessible to the public for about two and a half hours overnight but their operation has since been restored, Gilberto Paganotto, the head of Brazil's computer data agency, told Reuters.

Paganotto said the hackers did not access sensitive information from the sites. He said he was unaware of the source of the attack.

However, the website for Brazil's Estado de S.Paulo newspaper said that the Lulz Security group of hackers had taken credit for the attack.

LulzSec has made widely publicized assaults on Sony Corp, the CIA, News Corp's Fox TV, the British police Serious Organized Crime Agency and other targets. The attacks have mostly resulted in temporary disruptions to websites and the release of user credentials.

LulzSec said on Monday in a Twitter message that it was seeking to hack government websites to leak classified government information.

(Reporting by Jeferson Ribeiro and Brian Winter; editing by Mohammad Zargham)