FBI Director James Comey said Monday that there was "no information" that President Donald Trump was wiretapped by President Barack Obama during the 2016 presidential election. The director, testifying before a House Permanent Select Committee on Intelligence, also said that the agency was probing whether there was collusion between the Trump campaign and the Russian government. The US intelligence community has suggested that Russia hacked the Democratic National Committee during the election to embarrass Trump's presidential rival, Hillary Clinton.

"I have been authorized by the Department of Justice to confirm that the FBI, as part of our counter-intelligence mission, is investigating the Russian government's efforts to interfere in the 2016 presidential election, and that includes investigating the nature of any links between individuals associated with the Trump campaign and the Russian government, and whether there was any coordination between the campaign and Russia’s efforts. As with any counter-intelligence investigation, this will also include an assessment of whether any crimes were committed," Comey said.

Moments later, in response to a question about Trump's claims on Twitter earlier this month that Trump was wiretapped by Obama during the election, Comey responded: "The department has no information that supports those tweets."

On March 4, in a surprise tweet, Trump claimed: "How low has President Obama gone to tapp [sic] my phones during the very sacred election process. This is Nixon/Watergate. Bad (or sick) guy!" The president later followed up with other tweets saying the same thing.

Comey and Mike Rogers, the National Security Agency director, both testified that there was no evidence that Russian hacking intruded into US voting machines to change the outcome of the presidential election

Adam Schiff, an Intelligence Committee member and Democrat from California, said that "if the Trump campaign or anyone associated with it aided or abetted the Russians, it would not only be a serious crime, it would also represent one of the most shocking betrayals of democracy in history." He said that the hack into the Democratic National Committee was used "to help Donald Trump and harm Hillary Clinton."

Even before the hearing started, Trump tweeted that the Russia story is "is FAKE NEWS and everyone knows it!" And, as the intelligence hearing continued past the three-hour mark, the White House chimed in and said there was "no evidence" of collusion with Russia to interfere in the election.

Comey's announcement of the criminal investigation comes five weeks after Michael Flynn, Trump's national security advisor, resigned his position after it was disclosed he misled Vice President Mike Pence and others about conversations he had with the Russian ambassador to the United States. Flynn had originally denied he had conversations with Ambassador Sergey Kislyak about Russian sanctions in December.

Rep. Terri Sewell, a Democrat of Alabama and an Intelligence Committee member, said the bureau should investigate whether there was any "criminal intent" behind Flynn's actions.

Jeff Session, Trump's attorney general who oversees the FBI and the Justice Department, has said he would recuse himself from any investigation into Russian interference into the 2016 presidential election. Sessions had met twice with the Russian ambassador during the campaign. He did not reveal this in January during his confirmation hearings before the Senate Judiciary Committee.

One Trump campaign operative with potential ties to Russia includes Roger Stone Jr. He has been described as an off-and-on again advisor to Trump for several decades. He said he had contact on Twitter with Guccifer 2.0. That's a hacker believed to have ties to the Russian government who said he hacked the Democratic National Committee during the campaign.

“Even if he is a Russian agent, my cursory exchange with him happens after he releases the DNC stuff,” Stone said Saturday. “There’s only one exchange with him. I had no further exchanges.”

Adding to the political intrigue, Obama's director of national intelligence, James Clapper, said earlier this month that there was no Trump campaign collusion with Russia. "We had no evidence of such collusion," he said.

Meanwhile, Rep. Devin Nunes, the House Intelligence Committee chair and a Republican from California, said at the outset of the hearing that Trump may still have been the subject of surveillance during the election. "Let me be clear: We know there was not a wiretap on Trump Tower. However, it's still possible that other surveillance activities were used against President Trump and his associates."

Trump, for his part, made big headlines in July when he became the first presidential candidate to encourage a foreign government—Russia—to hack an opponent. The issue concerned Clinton's use of a private e-mail server during her tenure as secretary of state. Some 30,000 e-mails were deleted from Clinton's server because her staff determined they were personal and not connected to the investigation.

"I will tell you this, Russia: If you’re listening, I hope you’re able to find the 30,000 e-mails that are missing," Trump, the then-Republican nominee, said at a news conference in Florida. "I think you will probably be rewarded mightily by our press." Trump aides would later say that Trump was joking.

Even as the FBI investigates the Trump campaign, the Justice Department is investigating the FBI's pre-election handling of the Clinton e-mail probe. In July, Comey said Clinton should not be prosecuted in connection to her use of a private e-mail server.

He next publicly spoke about the situation on October 28—less than two weeks before the election—saying that the bureau discovered more e-mails relevant to the criminal inquiry that needed to be examined. Days later, on November 6—just two days before the election—Comey announced that the newly discovered e-mail was unrelated to the Clinton investigation.

Comey's actions prompted many after the election to conclude that he helped thwart Clinton's chances of winning the presidency—claims of which are now being investigated by the Department of Justice's inspector general.