Rep. Adam Schiff, the California Democrat who is the ranking member of the House Intelligence Committee, talking to reporters about the committee's investigation into Russia's involvement in the US election, on Capitol Hill on March 7. AP Photo/Cliff Owen The ranking Democratic congressman on the House Intelligence Committee quickly hit back at President Donald Trump's Monday-morning claim that hearings into his campaign's ties to Russia were "FAKE NEWS."

"Mr. President, the Russians hacked our election and interfered," the congressman, Rep. Adam Schiff of California, tweeted. "No one disputes this now, but you. This is what is called 'fact.'"

Schiff also chided the president for his unsubstantiated claims that President Barack Obama tapped the phones at Trump Tower before the election, as well as for White House statements that Schiff said had "collateral damage" with the US allies Britain and Germany.

Schiff defended the ongoing investigation into ties between Trump's campaign and Russian operatives to NBC's Chuck Todd on Sunday.

"There is circumstantial evidence of collusion," Schiff told Todd on "Meet the Press."

"There is direct evidence, I think, of deception and that's where we begin the investigation."

FBI Director James Comey and National Security Agency Director Adm. Mike Rogers are set to publicly testify Monday about their investigations into possible links between Russia and Trump's campaign as part of the House Intelligence Committee's investigation into allegations that Russia meddled in the US election.

"James Clapper and others stated that there is no evidence Potus colluded with Russia," Trump tweeted Monday morning. "This story is FAKE NEWS and everyone knows it!"

In follow-up tweets, the president claimed Democrats "made up and pushed the Russian story" to explain Democratic nominee Hillary Clinton's loss in the presidential election, and he called on Congress and the US intelligence community to look into classified-information leaks. Trump also questioned why Congress was not investigating the Clinton campaign's alleged ties to Russia.

Here are Schiff's tweets from Monday morning:

And here's what the president was tweeting Monday morning:

Sonam Sheth contributed reporting to this story.