FBI Director James Comey told senators Wednesday that Russia remains involved in American politics, saying he thinks the country poses the "greatest threat" to the U.S. political process of any in the world.

During a Senate Judiciary Committee oversight hearing, Republican Sen. Lindsey Graham — a foreign policy hawk — asked Comey "what kind of threat" Russia presents "to the democratic process."

"Certainly, in my view, the greatest threat of any nation on Earth, given their intention and their capability," Comey said.

The FBI director did not elaborate on what Moscow has done recently to try to influence American politics, but the bureau is actively investigating that question.

The U.S. intelligence community concluded that Russia interfered in the 2016 U.S. election, according to a declassified report released in January by the Office of the Director of National Intelligence.

"Russia's goals were to undermine public faith in the U.S. democratic process, denigrate Secretary Clinton, and harm her electability and potential presidency," that report said. "We further assess [Russian President Vladimir] Putin and the Russian Government developed a clear preference for President-elect Trump. We have high confidence in these judgments."

Trump repeatedly has denied that his campaign colluded with Russia, and has even cast doubt on whether the Kremlin tried to influence the election at all. Moscow also says that it did not try to interfere in the U.S. election, though it is widely believed to have interfered in the elections of multiple Western nations.