WASHINGTON - Fellow Republicans pressed President Donald Trump on Sunday to come clean about whether he has tapes of private conversations with former FBI Director James Comey and provide them to Congress if he does or possibly face a subpoena, as a Senate investigation into collusion with Russia or obstruction of justice extended to a Trump Cabinet member.

It was a sign of escalating fallout from riveting testimony from Comey last week of undue pressure from Trump, which drew an angry response from the president on Friday that Comey was lying.

Attorney General Jeff Sessions was in for sharp questioning by senators on the Senate Intelligence committee on Tuesday. Whether that hearing will be public or closed is not yet known.

"I don't understand why the president just doesn't clear this matter up once and for all," said Senator Susan Collins, R-Maine, a member of that committee, referring to the existence of any recordings.

She described Comey's testimony as "candid" and "thorough" and said she would support a subpoena if needed. Trump "should voluntarily turn them over," Collins said.

Senator James Lankford, R-Oklahoma, also a member of that committee, agreed the panel needed to hear any tapes that exist. "We've obviously pressed the White House," he said.

Trump's aides have dodged questions about whether conversations relevant to the Russia investigation have been recorded, and so has the president. Pressed on the issue on Friday, Trump said: "I'll tell you about that maybe sometime in the very near future."

Lankford said Sessions' testimony on Tuesday will help flesh out the truth of Comey's allegations, including Sessions' presence at the White House in February when Trump asked to speak to Comey alone. Comey alleges that Trump then privately asked him to drop a probe into former national security adviser Michael Flynn's contacts with Russia.

Comey also has said Sessions did not respond when he complained he didn't "want to get time alone with the president again". The Justice Department has denied that, saying Sessions stressed to Comey the need to be careful about following appropriate policies.

"We want to be able to get his side of it," Lankford said.

Trump on Sunday accused Comey of "cowardly" leaks and predicted many more from him. "Totally illegal?" he asked in a tweet. "Very 'cowardly!'"

Several Republican lawmakers also criticized Comey for disclosing memos he had written in the aftermath of his private conversations with Trump, calling that action "inappropriate". But, Lankford added that "releasing his memos is not damaging to national security".

Associated Press