Washington (CNN) House Republican Conference Chair Liz Cheney of Wyoming said on Tuesday that it is "shameful" to question the patriotism of Lt. Col. Alexander Vindman, the White House National Security Council's top Ukraine expert, who is testifying in the House impeachment inquiry.

"I also want to say a word about something else that's been going on over the course of the last several hours and last night, which I think is also shameful, and that is questioning the patriotism, questioning the dedication to country of people like Mr. Vindman, Lieutenant Colonel Vindman, who will be coming today, and others who have testified," Cheney said at a House GOP leadership weekly news conference.

"We need to show that we are better than that as a nation," Cheney said, adding, "Their patriotism, their love of country, we're talking about decorated veterans who have served this nation, who have put their lives on the line. It is shameful to question their patriotism, their love of this nation, and we should not be involved in that process."

Cheney did not specify to whom she was referring in her comment during the news conference, but it comes as Vindman, a decorated veteran who was born in Ukraine, has faced attacks from President Donald Trump and other Republicans.

Former Republican Rep. Sean Duffy of Wisconsin, who is a CNN contributor, argued during an appearance Tuesday on CNN that Vindman has an "affinity" for Ukraine and suggested that Vindman is more concerned about its defense than US policy.

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