A Russian former military operative with links to counterintelligence also attended Donald Trump Jr’s notorious meeting with a Russian lawyer about obtaining possibly incriminating information about Hillary Clinton.

Rinat Akhmetshin, a dual Russian-American citizen and lobbyist who has been accused of acting as “an unregistered agent for Russian interests” and with ties to Russian military intelligence service, or GRU, has confirmed he attended the meeting with lawyer Natalia Veselnitskaya.

Also participating in the meeting was a US-based Russian translator, Anatoli Samochornov, who had worked previously for Ms Veselnitskaya and the US State Department at various points.

Mr Akhmetshin said he accompanied Ms Veselnitskaya to Trump Tower on 9 June 2016. Although he had known and worked with Ms Veselnitskaya for a number of years, he said he had only learned about the meeting that day when she asked him to attend. He said he showed up in jeans and a T-shirt.

Mr Trump Jr’s account of the meeting, which has shifted several times, failed to mention the presence of Mr Akhmetshin, or the translator. Mr Trump Jr said he had agreed to the meeting, also attended by Mr Trump’s son-in-law, Jared Kushner, and campaign manager Paul Manafort, because he was told Ms Veselnitskaya had material damaging to Ms Clinton that was “high level and sensitive information [and] is part of Russia and its government’s support for Mr Trump”.

Mr Akhmetshin said Ms Veselnitskaya brought a plastic folder with her, containing printed documents that detailed what she believed could potentially be the flow of illicit funds to the Democratic National Committee. Ms Veselnitskaya presented the contents of the documents to the Trump associates and suggested that making the information public could help the Trump campaign, he said.

Mr Trump Jr asked the lawyer if she had all the evidence to back up her claims, according to Mr Akhmetshin, including whether she could demonstrate the flow of the money. But Ms Veselnitskaya allegedly claimed the Trump campaign would need to research it more.

After that exchange, Mr Trump Jr lost interest, Mr Akhmetshin said. “They couldn’t wait for the meeting to end,” he told the Associated Press.

Mr Akhmetshin said he does not know if Ms Veselnitskaya’s documents were provided by the Russian government. He said he thinks she left the materials with the Trump associates. It was unclear if she handed the documents to anyone in the room, or simply left them behind, he said.

Representative Adam Schiff, the top Democrat on the House of Representatives Intelligence Committee, said that the reports about Mr Akhmetshin add “another deeply disturbing fact about this secret meeting”.

Mr Trump Jr has insisted the meeting did not amount to much, that he was offered no information on Ms Clinton and that in truth Ms Veselnitskaya wanted to talk about the Magnitsky Act, a piece of US legislation that sanctions a handful of Russians the US believes might be linked to the 2009 death of lawyer Sergei Magnitsky.

Ms Veselnitskaya has denied offering any information to Mr Trump Jr and working for the Russian state.

Ms Veselnitskaya has denied working for the Russian government (AP)

Mr Akhmetshin has been closely associated with Ms Veselnitskaya for several years and has worked with her in an effort to overturn the Magnitsky Act. Mr Samochornov did translation for Ms Veselnitskaya in relation to her lobbying and legal work in the US.

In 2016, Ms Veselnitskaya’s client, Denis Katsyv, head of the company Prevezon, registered a nonprofit company in Delaware called the Human Rights Accountability Global Initiative Foundation (HRAGIF) in February 2016, which says its aim is to overturn an adoption ban on impacting American couples but which many believe is a front to lobby against the Magnitsky Act, the passage of which is said to have infuriated Vladimir Putin.

The HRAGIF’s registered lobbyist was Mr Akhmetshin, who took UK citizenship in 2009.

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Earlier this year, Senator Chuck Grassley, chairman of the Senate Judiciary Committee, said he wanted to learn more about Mr Akhmetshin’s activities.

In a letter to the Department of Homeland Security in April, Mr Grassley wrote: “I write to obtain information regarding Mr Rinat Akhmetshin, a Russian immigrant to the United States who has been accused of acting as an unregistered agent for Russian interests and apparently has ties to Russian intelligence.”

He added: “Mr Akhmetshin is a Russian immigrant to the US who has admitted having been a ‘Soviet counterintelligence officer’. In fact, it has been reported that he worked for the GRU and allegedly specialises in ‘active measures campaigns, subversive political influence operations often involving disinformation and propaganda.”

Rinat Akhmetshin has worked as a lobbyist on behalf of various Russia-related issues for a number of years (Bill Browder)

Mr Akhmetshin has denied that he worked for the GRU, saying he served in the Soviet Army from 1986 to 1988 after he was drafted but was not trained in spy tradecraft. He said his unit operated in the Baltics and was “loosely part of counterintelligence”.

The development has infuriated President Trump, who had hoped to get away from the Russia story, even as special prosecutor Robert Mueller continues a probe into possible links between the Trump campaign and Russia’s alleged effort to interfere in the 2016 election.

Mr Akhmetshin said he has not been contacted by Mr Mueller’s office or the FBI about the meeting with Mr Trump Jr. He said he is willing to talk with the Senate Judiciary Committee.

Earlier this week, Mr Trump was obliged to defend his eldest son, saying that “anyone” would have taken the meeting.

Speaking in France, where he was meeting with President Emmanuel Macron, he said: “I do think this, that taken from a practical standpoint … most people would’ve taken that meeting. It’s called opposition research, or even research into your opponent. I’ve only been in politics for two years, but I’ve had many people call up, ‘Oh gee, we have information on this factor or this person,’ or, frankly, Hillary.”

He added: “That’s very standard in politics. Politics is not the nicest business in the world.”

Mr Akhmetshin did not respond to repeated inquiries from The Independent. President Trump’s lawyers also failed to respond.