U.S. Defense Secretary Mark Esper holds a news conference with French Defense Minister Florence Parly (not pictured) at the residence of French Defense Minister in Paris, France, September 7, 2019. REUTERS/Christian Hartmann

Norfolk, VA (Reuters) - U.S. Defense Secretary Mark Esper said on Wednesday he had told his Ukrainian counterpart in a recent phone call that it was important for Kiev to deal with corruption, but declined to comment on a dramatic political showdown in Washington that threatens President Donald Trump’s presidency.

Democrats in the U.S. House of Representatives on Tuesday launched a formal impeachment inquiry into Trump, accusing him of seeking Ukraine’s help to smear Democratic rival Joe Biden ahead of next year’s election.

Esper told reporters he had spoken with his Ukrainian counterpart Andriy Zahorodnyuk a week or two ago, telling him it was important for Ukraine to deal with corruption and that it was an important issue for the U.S. government.

Trump asked Ukraine’s president in a July phone call to investigate whether former Vice President Joe Biden had shut down a probe into a gas company that employed his son, according to details of the call released by the Trump administration on Wednesday.

The call occurred after Trump had ordered the U.S. government to freeze nearly $400 million in American aid to Ukraine. The administration later released the aid.

Asked whether the White House decision to withhold military aid to Ukraine had harmed national security, Esper said: “I’m not going to get into any of that right now... As I’ve said on many occasions, I’m trying to keep (the Pentagon) out of politics and obviously that is all the news today.”

Esper told reporters he had also emphasized to Zahorodnyuk the need for European allies to also help Ukraine and that the burden should not fall on the United States.