WASHINGTON (Reuters) - A top White House official on Thursday acknowledged that U.S. President Donald Trump held back military aid for Ukraine earlier this year in part to pressure Kiev to look into allegations about the 2016 U.S. presidential election.

FILE PHOTO: Mick Mulvaney, Assistant to the President and Acting Chief of Staff, The White House, speaks during the Milken Institute's 22nd annual Global Conference in Beverly Hills, California, U.S., April 30, 2019. REUTERS/Mike Blake

Acting White House chief of staff Mick Mulvaney told a news conference that such action was “absolutely appropriate” and said it was part of Trump’s larger concerns about corruption in Ukraine.

“The look back to what happened in 2016 certainly was part of the things that he was worried about in corruption in that nation,” Mulvaney said.

Mulvaney added that the aid “ultimately then flowed.”

Asked about such transactions being a “quid pro quo,” he told reporters: “We do that all the time with foreign policy.”

Quid pro quo is a Latin phrase that means exchanging a favor for a favor.

Trump’s efforts to pressure Ukraine to investigate U.S. politics are at the heart of a congressional impeachment probe into whether the president acted inappropriately in using U.S. foreign policy to seek to impact his re-election.

Democrats, who control the House of Representatives, are examining Trump’s request to the president of Ukraine to dig up information on former U.S. Vice President Joe Biden, a 2020 Democratic presidential candidate, and his son Hunter Biden, who

served on the board of a Ukrainian gas company.

Mulvaney’s reference to 2016 refers to a debunked conspiracy theory that Ukraine and not Russia interfered in the U.S. election that year and that a Democratic Party computer server was being held somewhere in Ukraine.

(This story corrects Mulvaney’s first name in 2nd paragraph)