Hours after a key witness in the public impeachment hearings implicated the secretary of state in a "quid pro quo" scheme to pressure Ukraine to investigate President Trump's political rival, Mike Pompeo refused to directly address the allegation and said he wouldn't recuse himself from matters involving Ukraine.

Pompeo, who is in Brussels at a meeting of NATO foreign ministers, initially responded to a reporter's question by simply saying he "didn't have a chance to see any of that testimony." When pressed about the issue again by another reporter, he defended the Trump administration and the State Department.

"I know precisely what American policy was with respect to Ukraine. I was working on it, and I'm very proud of what we've accomplished," he said. "And I'm proud that President Trump led that effort to get our policy on Ukraine right. Our focus at the State Department is on making sure that we get our policy right, execute it flawlessly and deliver security on behalf of the American people."

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On Wednesday, Gordon Sondland, the U.S. Ambassador to the European Union, revised his closed-door testimony and contradicted Tuesday's witnesses. He confirmed there was a quid pro quo scheme to pressure Ukraine to investigate Mr. Trump's political rival in exchange for a White House meeting, and said in his opening statement that it was "no secret" and that "everyone was in the loop."

"Throughout these events, we kept State Department leadership and others apprised of what we were doing," he said. "State Department was fully supportive of our engagement in Ukraine affairs, and was aware that a commitment to investigations was among the issues we were pursuing."

Those investigations, Sondland testified, would also affect the U.S. military aid that had been paused.

"By the end of the August, my belief was that if Ukraine did something to demonstrate a serious intention to fight corruption, specifically addressing Burisma and 2016 server, then the hold on military aid would be lifted," Sondland told the House Intelligence Committee.

In a statement on Wednesday afternoon, a State Department spokesperson said, "Gordon Sondland never told Secretary Pompeo that he believed the president was linking aid to investigations of political opponents. Any suggestion to the contrary is flat out false."

Sondland made it clear that the push for investigations came from Mr. Trump.

"We all understood that these prerequisites for the White House call and White House meeting reflected President Trump's desires and requirements," he said.