President Donald Trump took to Twitter Thursday morning to call for House Intelligence Committee Chairman Adam Schiff's head.

Schiff "should be forced to resign from Congress," Trump wrote.

Schiff has insisted evidence showing Trump conspired with the Russians to win the 2016 election exists, and continued to push that narrative even after Attorney General William Barr announced that special counsel Robert Mueller's report cleared the president of collusion.

Trump's tweet came nust hours after the president attacked the California Democrat on the Fox News Channel's "Hannity," callingSchiff a "bad guy" who has been knowingly lying about him for nearly two years.

Trump's full tweet said:

Congressman Adam Schiff, who spent two years knowingly and unlawfully lying and leaking, should be forced to resign from Congress!

Within hours of Trump's tweet, Republicans on the House committee used the start of a hearing on Russia and efforts to influence U.S. elections to attack Schiff. They said all nine Republican panel members had signed a letter asking him to quit.

Schiff, who has not been accused by authorities of leaking classified information, responded strongly as the hearing erupted into acrimony.

He delivered a laundry list of the Trump campaign's contacts with Russians, from Donald Trump Jr. welcoming a Russian offer of dirt on Democratic rival Hillary Clinton, to short-lived national security adviser Michael Flynn secretly discussing U.S. sanctions on Russia with Moscow's ambassador.

"You might say that's all OK. You might say that's just what you need to do to win. But I don't think it's OK. I think it's immoral. I think it's unethical. I think it's unpatriotic and, yes, I think it's corrupt - and evidence of collusion," Schiff said.

White House adviser Kellyanne Conway called on Schiff to resign on Monday, a day after Barr released his four-page letter.

Senate Judiciary Committee Chairman Lindsey Graham, a close Republican ally of Trump's, has announced plans to examine the origins of the Trump-Russia probes. Some leading Republicans, including House Minority leader Kevin McCarthy, also have called on Schiff to resign from the panel or as committee chairman.

This report contains material from Reuters.