- At least four separate congressional investigations are underway into Moscow's election meddling.
- Democrats argue that the interference contributed to frontrunner Clinton's defeat.
FBI chief James Comey dealt Donald Trump a double blow Monday by confirming a probe into his election campaign's links to Russia last year while repudiating the president's claim that he was wiretapped by Barack Obama.
In a high-stakes public hearing televised live from the US Congress, Comey took the extraordinary step of confirming that the Federal Bureau of Investigation is investigating whether Trump campaign aides colluded with a Russian effort to influence the 2016 election.
Comey's bombshell statement undercut a White House effort to dismiss the controversy stalking Trump's young administration — with the president once more dismissing talk of his team's ties to Russia as "FAKE NEWS" as the hearing got underway.
The FBI chief refused to answer the questions of the House Intelligence Committee about exactly what and who its probe involves, citing the need to protect a sensitive, ongoing counterintelligence investigation.
But he confirmed to lawmakers that it "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."
And in a second setback for the Republican president, Comey firmly shot down his tweeted allegation earlier this month that his predecessor ordered a wiretap on Trump Tower, the real estate mogul's Manhattan residence and office.
"The Department of Justice has asked me to share with you that the answer is the same for the Department of Justice and all its components. The department has no information that supports those tweets," he told the hearing.
At least four separate congressional investigations are underway into Moscow's election meddling, which US intelligence chiefs said in January was directed by President Vladimir Putin and aimed to boost Trump's campaign over Democratic rival Hillary Clinton.
Democrats argue that the interference, in which Russian actors allegedly stole Democratic documents and communications and released them through WikiLeaks, contributed to frontrunner Clinton's defeat.
Confirming longstanding reports that his agency is probing a Russian effort to steer last year's vote, Comey dated the probe back to July last year, when the government became aware of the Democratic party hack.
Until Monday only a small group of legislators has been briefed in secret on this issue by US intelligence and law enforcement, and the public had not heard directly from them.