President-elect Donald Trump rejected a CIA finding that Russia intervened in the general election on his behalf, even as senior Senate Republicans and Democrats launch a joint review of Moscow’s actions.

Trump dismissed reports of an intelligence agency assessment that found hackers linked to the Kremlin had interfered in the U.S. election with the goal of helping Trump win, calling the notion “ridiculous.”

“I think it’s just another excuse” being put forward by Hillary Clinton supporters, Trump said on “Fox News Sunday,” adding, “I don’t believe it.”

Trump accused Democrats bitter over the general election outcome, of leaking the CIA assessment, suggesting such a move would be one part revenge and another pinning Clinton’s loss on Moscow.

“They have no idea if it’s Russia or China,” Trump said of the CIA. “It could be somebody sitting in a bed someplace. They have no idea.”