The hack comes almost two weeks after the biggest ransomware cyber attack in history hit multiple companies across 99 countries.
Qatar said on Wednesday its official state news agency had been hacked by an "unknown entity," and subsequently carried false remarks attributed to the country's Emir, Sheikh Tamim bin Hamad al Thani.
"The Qatar News Agency website has been hacked by an unknown entity," reported the Government Communications Office in a statement.
"A false statement attributed to His Highness has been published."
It added that an investigation would be launched into the security breach.
The statement attributed to the emir focused on sensitive regional political issues with other nations in the region, including Iran and Israel, and also Doha's relationship with new US President Donald Trump.
The "false statement" was reported by broadcasters in the United Arab Emirates and caused a stir on social media in the Gulf, before Doha scrambled to deny the claims.
The communications office added that the "State of Qatar will hold all those" who committed the breach accountable.
The attack comes almost two weeks after hacking tools believed to have been developed by the US National Security Agency were exploited by hackers to infect hundreds of thousands of computers in at least 99 countries.
The extortion attacks, which were carried out with a version of WannaCry ransomware, locked computers and held users' files for ransom, is believed to be the biggest of its kind on record.
It disrupted services in nations as diverse as the US, Russia, Ukraine, Spain and India.