WASHINGTON – As a National Security Council official testified in the impeachment inquiry, President Donald Trump and his allies responded by attacking Lt. Col. Alexander Vindman's credibility and nationality, drawing rebukes from attorneys and even some Republicans.

"Supposedly, according to the Corrupt Media, the Ukraine call 'concerned' today’s Never Trumper witness," Trump said during a morning-long series of angry tweets criticizing the impeachment process. "Was he on the same call that I was? Can’t be possible! Please ask him to read the Transcript of the call. Witch Hunt!"

Some Trump supporters, meanwhile, stressed that Vindman, a Ukraine expert with the National Security Council, was born in Ukraine, questioning his patriotism in a manner that drew condemnation from legal analysts.

"They are so desperate to smear and attack anyone who dares testify against the president," said Bradley P. Moss, an attorney who specializes in national security issues.

Some Republican lawmakers also criticized the tactic.

Rep. Liz Cheney, R-Wyoming, a Trump supporter, decried the attacks on Vindman and others, telling reporters: "It is shameful to question their patriotism, their love of this NATION."

Senate Majority Leader Mitch McConnell, R-Kentucky., said he would not address the merits of the House impeachment probe, but added: “I’m not going to question the patriotism of any of the people coming forward."

Though he claimed he had never heard of Vindman, Trump later described him as "a Never Trumper."

"How many more Never Trumpers will be allowed to testify about a perfectly appropriate phone call when all anyone has to do is READ THE TRANSCRIPT!" Trump later tweeted.

Vindman, a career military officer who was wounded in Iraq, said he told superiors that Trump may have been undermining national security as he attempted to tie aid to Ukraine to its willingness to investigate U.S. political opponents, including Democratic presidential candidate Joe Biden.

The demand was reflected in a July phone call between Trump and Ukrainian President Volodymyr Zelensky

"I did not think it was proper to demand that a foreign government investigate a U.S. citizen, and I was worried about the implications for the U.S. government’s support of Ukraine," Vindman wrote in his prepared remarks obtained by USA TODAY.

In what looked like a coordinated effort to undermine Vindman's credibility, Trump and allies spent most of the day attacking him – including the fact he was born in Ukraine.

Saying Vindman has "an affinity" for Ukraine, ex-U.S. Rep. Sean Duffy, R-Wisc., told CNN that "it seems very clear that he is incredibly concerned about Ukrainian defense. I don't know that he's concerned about American policy."

Smears about some kind of "dual loyalty" are "reprehensible and desperate," said Neal Katyal, an acting solicitor general during the Barack Obama administration.

Chris Lu, the White House Cabinet Secretary for President Barack Obama, noted that Vindman was wounded in Iraq.

"When the facts are on your side, argue the facts," Lu tweeted. "When the facts aren’t on your side, argue about process. When a decorated Iraq War vet wounded in an IED attack delivers devastating testimony, question his loyalty to the country. This is what the GOP has been reduced to."

In addition to attacking the witness, Trump again decried the entire impeachment process, and again called for identifying the whistleblower whose complaint began the process. "Where’s the Whistleblower?," he said in another tweet, saying that anything beyond the transcript of his call "is made up garbage."

At another point, Trump sought to shift the political agenda: "The Do Nothing Democrats are working hard to make everyone forget the Best Economy Ever, the monumental weekend raid, Tax Cuts, the Rebuilding of our Military, etc. The Impeachment Hoax is a disgrace. Read the transcript!"