Elliott Broidy, a top Republican fundraiser, sued Qatar on Monday, accusing the Gulf state of pilfering and leaking emails in retribution for his attempts to influence the Trump administration in favour of regional rivals of Qatar, reports Khaleej Times.
In the lawsuit, filed in US District Court in Los Angeles, Broidy accused Qatar and its agents of hacking into his and his wife's email accounts and providing the stolen documents, via US-based lobbyists, to media outlets in order to plant damaging articles about him.
The lawsuit, which seeks unspecified damages, says some of the leaked materials were doctored.
"We believe the evidence is clear that a nation state is waging a sophisticated disinformation campaign against me in order to silence me," Broidy said in a statement.
The lawsuit adds a new dimension to a diplomatic crisis in the Gulf set off when the United Arab Emirates, Saudi Arabia, Bahrain and Egypt imposed sanctions on Qatar last June.
The boycott was based on allegations that Qatar supports militants and regional foe Iran. Qatar denies the charges.
Jassim Al Thani, a spokesman at Qatar's embassy in Washington, described the lawsuit as an attempt by Broidy to divert attention from media scrutiny on his activities.
"It is Mr. Broidy, not Qatar, who orchestrated nefarious activities designed to influence Congress and American foreign policy," Al Thani said in a statement.
Broidy cited several articles that he believes were prompted by the leaking of his emails and other documents.
Broidy claims Al Jazeera published an article on March 8 based on falsified documents accusing him of entering into a lobbying contract in 2014 with a Russian bank under US sanctions.
Al Jazeera did not immediately respond to an email seeking comment.
Broidy accused Nicolas Muzin, a Washington-based lobbyist whose firm has a $300,000 per month contract with Qatar, of helping to wage a campaign to discredit Broidy's efforts to "educate the American people about Qatar." Muzin was also named as a defendant in the suit.
"Mr Broidy's lawsuit is an obvious attempt to draw attention away from his controversial work, and is as flimsy as the promises he reportedly made to his clients," Muzin said in a statement, saying he was proud of the work he did for Qatar.