WASHINGTON - A federal judge on Wednesday ruled that Paul Manafort, US President Donald Trump's former campaign chairman, breached his plea agreement by intentionally lying to Special Counsel Robert Mueller, the FBI and the grand jury.

Manafort "intentionally made multiple false statements" concerning matters related to Mueller's probe into the alleged Russia meddling in the 2016 US elections, said Judge Amy Berman Jackson in the US District Court for the District of Columbia.

At a closed-door hearing, the judge said there was a "preponderance" of evidence that Manafort lied on three different topics, including his communications with his former business partner Konstantin Kilimnik, the codefendant who the FBI says has ties to Russian intelligence, according to local media reports.

Kilimnik, who lives in Russia, was charged alongside Manafort with conspiracy and obstruction of justice. He has yet to appear in a US court to face the charges.

The ruling voids the federal government's obligations under Manafort's plea deal to offer him leniency in exchange for his cooperation in the Mueller probe. It also means that Manafort will not be credited for his cooperation with prosecutors.

The charges against Manafort largely stem from his time working for a pro-Russian leader in Ukraine years before the 2016 US elections. They do not directly address any alleged collusion between Trump associates or officials and the Russian government, which the Mueller team has been investigating since May 2017.

Trump has repeatedly attacked the Mueller probe as a "rigged witch hunt."