President Trump said on Thursday that he has no investments in Russia and sent a "certified" letter to Sen. Lindsey Graham to prove it.

Trump's ties to Russia have been a point of fascination and subject of investigation since the 2016 campaign in which the U.S. intelligence community concluded that Russian operatives interfered in the election process. Speculation swirled over the weekend after an author reportedly said that in 2014 one of Trump's son, Eric Trump, claimed that all funding for Trump golf courses comes from Russia. Eric Trump later responded to that report, calling it "complete garbage."

During an interview Thursday, NBC News' Lester Holt asked Trump to respond to the Senate Intelligence Committee seeking information from the Treasury Department's financial crimes unit about his finances and his family's businesses.

"Can you tell us whether you, your family, your businesses, your surrogates have accepted any investments, any loans from Russian individuals or institutions?" Holt asked.

Trump replied that he had just sent a letter from "one of the most prestigious law firms in the country" about not having anything to do with Russia, to Graham, R-S.C., who is a member of the Armed Services and Judiciary committees.

"I have no investments in Russia, none whatsoever. I don't have property in Russia," he said.

The president claimed many people "thought" he owned office building in Russia and stressed that he has filed "hundreds of pages worth of documents" with the Federal Elections Bureau.

Trump explained further: "I have had dealings over the years where I sold a house to a very wealthy Russian many years ago. I had the Miss Universe pageant, which I owned for quite a while. I had it in Moscow long time ago, but other than that I have nothing to do with Russia."

Something Trump has not done, however, is release his tax returns, using an IRS audit as justification for not doing so. Trump could choose to release his tax returns if he wanted to regardless of whether he is being audited.

Trump said he assumes Graham will make the letter public.

Graham's office did not immediately return the Washington Examiner's request for comment or a copy of the letter.

Editor's note: This story has been corrected to show Lindsey Graham is a senator from South Carolina.