WASHINGTON -- A former top U.S. Justice Department official has testified that she told the White House in January that President Donald Trump's national security adviser was in danger of being compromised by Russia.
Sally Yates made the remarks during highly anticipated testimony on May 8 before a Senate Judiciary subcommittee.
The panel is one of several looking into the scope and scale of ties between Trump's associates and Russian officials. The FBI is also conducting its own investigations into those communications.
The central focus of the Senate hearing was Trump's first national security adviser, Michael Flynn, who was forced to resign in February after he reportedly misled administration officials about his contacts with Sergei Kislyak, Russia's ambassador to the United States.
After news media reported on Flynn’s interactions with Kislyak, Vice President Mike Pence publicly defended Flynn.
Yates, who served as acting attorney general under Trump until she was fired in late January, told senators that, after the president's inauguration that month, she warned the White House's legal counsel -- twice in person and once in a phone call -- of Flynn's contacts with Russian officials.
"We felt like it was critical that we get this information to the White House, in part because the vice president was making false statements to the public and because we believed that General Flynn was possibly compromised," Yates said.
"Logic would tell you that you don't want the national security adviser to be in a position where the Russians have leverage over him," she said.
The last conversation Yates had with White House legal officials came on January 26, two days after Flynn was interviewed by the FBI about his Russian communications, she testified.
Flynn resigned about two weeks later, on February 13.
Yates, a holdover from the Obama administration, was fired by Trump after she refused to defend a controversial travel ban targeting seven predominantly Muslim countries.
After the hearing, Trump took to Twitter to bash the media coverage and deny any collusion between his aides and Russia.
"The Russia-Trump collusion story is a total hoax, when will this taxpayer funded charade end?" he asked.
Trump noted that former National Intelligence Director James Clapper, who also testified at the hearing, repeated his view that U.S. intelligence investigations last year found "no evidence of collusion" between Russia and the Trump campaign.
"Everybody, including the fake media already knows" this, Trump tweeted.
Meanwhile, White House spokesman Sean Spicer confirmed to reporters on May 8 that Obama himself had made it clear to Trump that he was not "a fan" of Flynn.
That warning came during a face-to-face meeting between Obama and Trump on November 10, two days after Trump's victory in the November 8 election.
Spicer added that this "frankly shouldn't come as a surprise to anyone, given that General Flynn had worked for President Obama, was an outspoken critic of President Obama's shortcomings."
Spicer's comments followed media reports earlier in the day citing other ex-officials in Obama's administration as saying Obama had warned Trump against hiring Flynn.
Also testifying before the Senate panel was the former director of national intelligence, James Clapper, who oversaw the release of an extraordinary report in January accusing Russia of waging an aggressive effort to influence the 2016 presidential election.
Clapper told the Senate panel that British officials had shared information about links between Trump associates and Russian officials in the months prior to the November 8 election.
The issue of Russia's alleged meddling in the election and allegations of collusion with Russian officials have dogged Trump's administration from its very early days, overshadowing some of his efforts at legislating and policymaking.
Trump has accused the news media and his political opponents of seeking to undermine his presidency with what he has called a "fake" Russia story.
Trump himself weighed in ahead of the May 8 Senate hearing, suggesting on Twitter that the Obama administration was to blame since it granted Flynn a high-level security clearance.
Obama fired Flynn as head of the Defense Intelligence Agency in 2014.