U.S. investigators believe Russian hackers breached Qatar's state news agency and planted a fake news report that contributed to a crisis among the U.S.' closest Gulf allies, according to US officials briefed on the investigation, CNN reports exclusively.

The FBI recently sent a team of investigators to Doha to help the Qatari government investigate the alleged hacking incident, Qatari and US government officials say.

Intelligence gathered by the US security agencies indicates that Russian hackers were behind the intrusion first reported by the Qatari government two weeks ago, US officials say. Qatar hosts one of the largest US military bases in the region.

The alleged involvement of Russian hackers intensifies concerns by US intelligence and law enforcement agencies that Russia continues to try some of the same cyber-hacking measures on US allies that intelligence agencies believe it used to meddle in the 2016 elections.

U.S. officials say the Russian goal appears to be to cause rifts among the U.S. and its allies. In recent months, suspected Russian cyber activities, including the use of fake news stories, have turned up amid elections in France, Germany and other countries.

It's not yet clear whether the U.S. has tracked the hackers in the Qatar incident to Russian criminal organizations or to the Russian security services blamed for the US election hacks. One official noted that based on past intelligence, "not much happens in that country without the blessing of the government."

The FBI and CIA declined to comment. A spokeswoman for the Qatari embassy in Washington said the investigation is ongoing and its results would be released publicly soon.

The Qatari government has said a May 23 news report on its Qatar News Agency attributed false remarks to the nation's ruler that appeared friendly to Iran and Israel and questioned whether President Donald Trump would last in office.