The Democratic-led U.S. House of Representatives' impeachment inquiry against President Donald Trump on Tuesday questioned George Kent, a U.S. career diplomat who has spent much of his career fighting corruption in Ukraine and elsewhere.

The investigation is focused on a July 25 phone call in which Trump pressed Ukrainian President Volodymyr Zelenskiy to look into unsubstantiated allegations against former Vice President Joe Biden, a top contender for the Democratic nomination to challenge Trump in the 2020 presidential election, and Biden's son, Hunter Biden.

The younger Biden, 49, denied doing anything improper www.reuters.com/article/us-usa-trump-whistleblower-biden/hunter-biden-defends-overseas-work-in-interview-but-expresses-regret-idUSKBN1WU1PS in past work for a Ukrainian energy company but expressed regret in an interview with ABC News aired on Tuesday over how it has been used to attack his father. Joe Biden has rejected Trump's allegations of corruption.