Trump Expected To Release Ukraine Phone Transcript

US President Donald Trump says his administration will release "the complete, fully declassified and unredacted" transcript of his call with Ukrainian President Volodymyr Zelensky.

In a tweet, Trump said the transcript would be released on Wednesday and would show the call was "totally appropriate" and that he had not pressured Zelensky to investigate Democratic presidential hopeful Joe Biden and there had been no quid pro quo for US aid in exchange for a probe.

Trump confirmed on Tuesday he had withheld nearly $US400 million in US aid to Ukraine.

In remarks to reporters at the United Nations over the intensifying political controversy, Trump sought to portray that there was nothing sinister about the withholding the aid, saying he wanted Europe and not just the US to step up and provide Ukraine assistance. The money was later released by the Trump administration.

"There was never any quid pro quo," Trump told reporters at the UN, using a Latin phrase meaning a favour that is exchanged for a favour.

In Washington, House of Representatives Speaker Nancy Pelosi, a Democrat, was to meet later on Tuesday with Democratic lawmakers to consider impeaching the Republican president as more lawmakers voiced support for the action.

Pelosi provided no details about her planned statement, which she told reporters would come at 5pm local time.

READ MORE: Explained: Trump, Ukraine, Biden And How It Could Lead To Impeachment

Biden would make a statement on the issue later in the day where he will say "Trump's latest abuses are on top of all of his prior abuses," a 2020 presidential election campaign spokesman said.

"He's going to call on Trump to comply with all of congress' outstanding lawful requests for information -- in the Ukraine matter, and in the other investigations -- and if Trump doesn't comply, congress has no choice but to impeach," the spokesman said.

Trump is seeking re-election next year and Biden, the former US vice president, is the front runner for the Democratic presidential nomination.