A Russian-American businessman who donated a substantial sum to Donald Trump’s 2016 presidential election effort boasted to a senior figure in Moscow that he was “actively involved” in the Republican candidate’s campaign, the Guardian can reveal. Simon Kukes said he was helping Trump with “strategy development” and shared photos of his 29-year-old Russian girlfriend posing with the future president. Kukes made the claims to Vyacheslav Pavlovsky, a career Kremlin official and former ambassador to Norway. Pavlovsky is currently vice-president of Russian Railways. The disclosure raises questions about the role played by Kukes in the run-up to the election and what information, if anything, was being relayed by him to his associates in Russia. Kukes’s donations began two weeks after the meeting at Trump Tower in June 2016, when Donald Trump Jr, Paul Manafort, and Jared Kushner discussed “dirt” on Hillary Clinton with a Russian lawyer. In total Kukes gave $273,000 (£207,000) to Trump Victory – a fundraising committee that distributes donations between the candidate, the Republican National Committee (RNC) and state Republican parties. He had no previous history of giving money to political causes. During this period he was in regular contact with Pavlovsky. In one email written in July 2016, Kukes wrote in Russian: “I am actively involved in Trump’s election campaign, and am part of the group on strategy development.” Kukes said that he would be in Switzerland from 20 July until 2 August, and asked Pavlovsky if he wanted to meet there. Kukes emailed again a week later, saying he would like to introduce Pavlovsky to a “close friend”, a Moscow oil executive, “who has just flown in”. They were discussing “very interesting projects for Russia and the US”, he wrote, adding: “I hope one of them will materialise.” One US intelligence expert described Kukes’s communications with Pavlovsky as suspicious. “To me this reads like an email exchange between a source and a handler, or a source and headquarters,” Lindsay Moran, a former CIA officer, told NBC News after reviewing the email exchanges. Since giving money to Trump, Kukes has avoided publicity. He founded a Houston-based consultancy, Nafta Consulting LLC, and invested in a company that develops US shale and oil assets. He was an investor in Promstroy, an oil services company.