Washington, Nov 4

The anonymous whistleblower whose complaint triggered an impeachment inquiry into US President Donald Trump has agreed to answer written questions from Republican lawmakers, an attorney said.

"Our legal team offered Republicans the direct opportunity to ask written questions of #whistleblower," Mark Zaid, who is representing the whistleblower, said in a series of tweets on Sunday.

Zaid said they have offered both Republican and Democratic members of the House and Senate Intelligence Committees to have his client answer questions "in writing, under oath &andpenalty of perjury", reports Xinhua news agency.

The attorney, specifically, said they have offered to Devin Nunes, the Republican ranking member of the House Intelligence Committee, the "opportunity for Minority to submit through legal team written questions" to the whistleblower.

"Qs cannot seek identifying info, regarding which we will not provide, or otherwise be inappropriate. We will ensure timely answers," he said.

"Being a whistleblower is not a partisan job nor is impeachment an objective. That is not our role."

In an anonymous complaint earlier this year, the whistleblower raised concerns about the White House's interactions with Ukraine, including a July 25 phone call between Trump and his Ukrainian counterpart Volodymyr Zelensky which prompted House Speaker Nancy Pelosi to initiate the impeachment inquiry on September 24.

Trump was alleged to have abused power by using a military aid to pressure Zelensky into investigating former US Vice President Joe Biden, a top-tier 2020 Democratic presidential contender, so as to help his re-election campaign.

Trump has denied any wrongdoing or a "quid pro quo" and has termed the inquiry as a "witch hunt".

The White House has also dismissed the allegations and made clear that it would not cooperate with House investigators by providing documents or witnesses because it considered the ongoing impeachment inquiry unfair and illegitimate.

Zaid's offer came as Trump on Sunday called for the revealing the whistleblower's identity, while attacking the complaint's credibility.

"The whistleblower should be revealed because the whistleblower gave false stories. Some people would call it a fraud; I won't go that far," Trump told reporters at the White House.

Meanwhile, House Minority Leader Kevin McCarthy on Sunday suggested that written testimony would not satisfy Republicans.

"When you're talking about the removal of the president of the United States, undoing democracy, undoing what the American public had voted for, I think that individual should come before the committee," the California Republican told CBS News.

"He needs to answer the questions."

The Democratic-controlled House approved mostly along party lines a resolution last week that establishes procedures for public hearings in the impeachment inquiry and the release of deposition transcripts, among other things.

Trump whistleblower willing to answer written queries from Republicans