WASHINGTON, D.C. (WVEC)-- The nation's intelligence agency chiefs said Tuesday there's no doubt the Russians interfered in the 2016 elections with sophisticated cyber operations and false information social media campaigns, and there's no doubt they will keep trying.

President Donald J. Trump has called the Russia investigation a witch hunt and a hoax and said that he believes Vladimir Putin's claims of innocence.

But the US intelligence leaders were adamant: It happened, Russia meddled, and it's likely to happen again.

"This is is not going to change or stop," said the National Security Agency's Director, Admiral Michael Rogers, testifying before the Senate Select Committee on Intelligence.

The panel's vice chairman, Virginia Senator Mark Warner, said the threat is real.

"Make no mistake," he said. "This threat did not begin in 2016, and it certainly didn't end with the election. What we are seeing is a continuous assault by Russia to target and undermine our democratic institutions, and they are going to keep coming at us."

Director of National Intelligence Daniel Coats said America must redouble its efforts in this area.

"We need to inform the American people this is real, this is happening, and the resilience needed for s to stand up and say, we're not going to allow some Russian to tell us how to vote, how we ought to run our country," he said. "I think there needs to be a national cry for that."

Under questioning from Maine Senator Susan Collins about the President's attacks on the FBI, FBI director Christopher Wray said, "It's the finest group of professionals and public servants I could hope to work for."