Trump says exerted 'no pressure whatsoever' on Ukraine

President Donald Trump maintained Wednesday that he had exerted "no pressure" on Ukraine, as the White House released a call transcript confirming he had asked Kiev to probe his political rival Joe Biden.

"There was no pressure whatsoever," Trump told reporters on the sidelines of the United Nations General Assembly, a day after Democrats seized on the explosive call to launch an impeachment process.

"It was a friendly letter, there was no pressure," Trump repeated, denouncing what he called "the single greatest witch hunt in American history.