The White House says President Donald Trump is sending a certified letter to Sen. Lindsey Graham attesting that the president has no connections to Russia.

Graham told CNN on Tuesday he wants to explore possible ties between Trump’s businesses and Russia. The South Carolina Republican chairs a Senate Judiciary subcommittee that is investigating Russian interference in the 2016 presidential election.

White House spokesman Sean Spicer says Trump has asked a Washington law firm to send a certified letter to Graham stating that he has no connections to Russia.

Spicer says Trump has no business in Russia or ties to the country. He says based on that Graham’s inquiry “should be a really easy look.”

U.S. intelligence agencies have concluded that Russia interfered in the election in attempt to help Trump.