President Donald Trump on Sunday accused Rep. Adam Schiff of leaking classified information on Russian interference in the 2020 U.S. election to hurt Democratic presidential front-runner Bernie Sanders.

Speaking to reporters as he left the White House for a trip to India, Trump said he had not been briefed on intelligence that Russia was aiming to boost the campaign of Sanders, a U.S. senator from Vermont, and he called for a probe into Schiff for the leak. Schiff, a Democrat, denied the allegation.

A congressional source told Reuters on Friday that intelligence officials had told lawmakers Russia appears to be engaging in disinformation and propaganda campaigns to help both Sanders and Trump, who is seeking re-election.