A witness in the Russia investigation has testified that Trump associate Erik Prince helped arrange a 2017 meeting in the Seychelles islands with a Kremlin ally as part of an effort to establish a backchannel of communication between the US and Russia, and to discuss US-Russia relations under the Trump administration.

The revelation appears to contradict Prince's testimony before the House Intelligence Committee last year, when he told the panel his meeting with the Kremlin ally, Russian investor Kirill Dmitriev, happened by chance.

The unnamed witness' testimony also comes amid reports that George Nader, an adviser to the Emirati crown prince who attended the Seychelles meeting on behalf of the United Arab Emirates, is cooperating with Mueller and testified before a grand jury earlier this year.

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The special counsel Robert Mueller has learned from a witness that a 2017 meeting in the Seychelles islands between an associate of President Donald Trump and a top Kremlin ally was arranged in order to establish a backchannel of communication between the US and Russia, The Washington Post reported Wednesday.

Mueller is investigating Russia's interference in the 2016 US election, including whether members of Trump's campaign colluded with Moscow to tilt the race in his favor.

The meeting in question was between Blackwater founder Erik Prince and Russian investor Kirill Dmitriev. George Nader, a Middle East expert and an adviser to the United Arab Emirates' Crown Prince Mohammed bin Zayed Al-Nahyan, was also in attendance as the crown prince's representative.

Nader testified before a grand jury about the meeting earlier this year, and according to The Post, a witness told Mueller that the Seychelles meeting was set up in advance to discuss US-Russia relations. The testimony appears to contradict Prince's account of the meeting before the House Intelligence Committee last year, when he told the panel that it had occurred by chance.

Prince reportedly approached Crown Prince Mohammed, with whom he has a long business relationship, following a December 2016 meeting between the prince and senior adviser Jared Kushner, former White House chief strategist Steve Bannon, and former national security adviser Michael Flynn.

Prince told the Emirati crown prince he was authorized to act as an unofficial surrogate for Trump, and then asked whether Crown Prince Mohammed could set up a meeting with Dmitriev, who heads a sanctioned Russian investment fund and is closely allied with Russian President Vladimir Putin.

While Nader attended the Seychelles meeting, which took place on January 11, 2017, as Crown Prince Mohammed's representative, Emirati officials believed Prince represented the Trump team and that Dmitriev represented Putin.

Prince told the House Intelligence Committee last year that he knew Dmitriev was a Russian fund manager but did not know it was a sanctioned fund that was controlled by the Russian government.

Prince also denied that he attended the meeting as an official representative of the incoming administration, saying instead that he traveled to the Seychelles to meet with potential business customers from the UAE.

Prince resides in the UAE and has been associated with Nader for over a decade. It is unclear why, if he was interacting with potential Emirati customers, he had to travel to the Seychelles to meet them.

During the meeting, Prince told lawmakers on the House Intelligence Committee, the customers "mentioned a guy who I should also meet who was also in town," who turned out to be Dmitriev.

"At the end, one of the entourage says, 'Hey, by the way, there’s this Russian guy that we’ve dealt with in the past. He’s here also to see someone from the Emirati delegation. And you should meet him, he’d be an interesting guy for you to know, since you’re doing a lot in the oil and gas and mineral space,'" Prince told lawmakers.

When he met Dmitriev, they discussed a range of topics, and Dmitriev stressed that he wished Russia and the US could resume normal trade relations, Prince said. He added that they spoke for no more than 30 minutes.

After the Seychelles meeting, Dmitriev also met with Anthony Scaramucci, who would later become the White House communications director, at the World Economic Forum in Davos, Switzerland.

Russian state media quoted Scaramucci as saying, after his meeting with Dmitriev, that the Obama administration's new sanctions on Russia — which were imposed that month to penalize it for interfering in the 2016 election — were ineffective and detrimental to the US-Russia relationship.

One month before Prince met with Dmitriev, Kushner also reportedly proposed a secret back-channel of communication between the Trump team and Moscow using Russian facilities.