A former Trump campaign manager has lashed out at Democrats during the first congressional hearings to explore possible impeachment of the president.
Corey Lewandowski repeatedly refused to answer questions during an ill-tempered House of Representatives session that devolved into shouting matches.
One Democratic lawmaker called for Mr Lewandowski to be held in contempt of the proceedings.
President Donald Trump praised Mr Lewandowski's "beautiful" remarks.
Mr Lewandowski testified under oath on Tuesday before the House judiciary committee, which had issued him with a legal summons, known as a subpoena, to give evidence.
In fractious exchanges with Democrats, he said he could not answer any question about his conversations with Mr Trump.
On the eve of the hearing, the White House had instructed Mr Lewandowski not to divulge his discussions with the president.
White House lawyers sat behind Mr Lewandowski during the session.
He was fired by Mr Trump in June 2016 and never worked in the White House, but remains a staunch supporter.
The president's fellow Republicans criticised the Democratic-controlled committee hearing as unfair and unsuccessfully moved to adjourn it.
Top Republican Doug Collins tweeted: "In the absence of a proper floor vote to authorise an impeachment inquiry, today's business represents a regular oversight hearing, masquerading as impeachment to appease a liberal base".
Mr Lewandowski was asked about his testimony last July to former Special Counsel Robert Mueller, who investigated the president.
The Mueller report did not determine that Mr Trump had conspired with Russia to sway the 2016 US election, but it presented evidence that the president attempted to thwart the justice department inquiry.
The special counsel's investigators detailed how Mr Trump asked Mr Lewandowski in summer of 2017 to meet the then-attorney general and direct him to limit the Russia investigation, and tell him he was fired if he failed to comply.
But Mr Lewandowski told the committee on Tuesday that he went to the beach with his family and so was unable to do the president's bidding.
Mr Lewandowski also told the panel he did not believe the president had asked him to do anything illegal.
When Democrat Hank Johnson suggested Mr Lewandowski had "chickened out", he replied: "I went on vacation."
Congressman Eric Swalwell repeatedly asked Mr Lewandowski to read aloud his evidence to Mr Mueller, but the witness refused.
"Are you ashamed of the words you wrote down?" asked Mr Swalwell, a California Democrat who recently ended his own White House campaign.
Mr Lewandowski mockingly called the lawmaker "President Swalwell", and said he should read the passage himself.
Mr Lewandowski - who is considering a run for a US Senate seat in New Hampshire - accused the lawmakers of ranting and not asking proper questions.
In his opening statement, he called on Democrats to stop focusing on "petty and personal politics" and "going down rabbit holes".
He also attacked the Mueller inquiry for being "populated by many Trump haters who had their own agenda to try and take down a duly elected President".
Watching from Air Force One, Mr Trump praised his former campaign adviser on Twitter.
Such a beautiful Opening Statement by Corey Lewandowski! Thank you Corey! @CLewandowski_— Donald J. Trump (@realDonaldTrump) September 17, 2019
Two other former White House aides, Rick Dearborn and Rob Porter, followed White House advice not to show up at Tuesday's hearing.
The judiciary committee has said it hopes to decide whether to recommend impeachment to the full House by the end of the year.
However, the president's foes do not have the political muscle in Congress to remove him from office.