The chairman and vice chairman of the Senate intelligence committee put out a statement on Thursday stating there is no indication Trump Tower was the subject of US government surveillance, another blow to President Donald Trump's twitter allegations that former President Barack Obama tapped his phones.
Next week Federal Bureau of Investigation director James Comey and National Security Agency director Mike Rogers will testify before a Congressional committee about what evidence their agencies have about Russia's meddling in the U.S. elections.
When President Trump accused Barack Obama of wiretapping him when he was a candidate, Obama denied it and Democrats criticized him for levying the claim without evidence.
The Justice Department was required to hand over any evidence of Trump Tower's wiretapping to the House Intelligence Committee by Monday.
Other influential Republicans, including Sen. Trump has said he had nothing to do with Russian Federation and described the probes as witch-hunts.
Comey is slated to testify Monday before the House intelligence committee.
Carlson challenged Trump, asking him why he wouldn't wait to tweet about a serious charge until he had evidence to support his statements. Richard Burr (R-N.C.) and Mark Warner (D-Va.) said in a joint statement, providing no other details.
And in case his point was lost, Nunes made the point that if Trump's claim was to be taken literally, "then clearly the president is wrong".
Oklahoma Rep. Tom Cole says he's seen nothing to back up Trump's unproven claim, and added: "I think the president, President Obama, is owed an apology in that regard, because if he didn't do it we shouldn't be reckless in accusations that he did".
Over in the House, Mr. Nunes has begun a similar inquiry into the Kremlin's behind-the-scenes attempts to influence the presidential election in Mr. Trump's favor.
In response to Trump's claims and a request from the House intelligence committee, the Justice Department is doing its own review of whether Trump or any of his associates were the subject of surveillance.
The difference between the substance of the New York Times article and what Trump claimed in his tweet is significant, because Trump's tweet alleges Obama possibly acted outside the law to harm a political opponent, whereas the New York Times described aspects of an FBI investigation.
The Senate Intelligence Committee said in its Thursday statement that it did not find evidence of "surveillance", using the broader term instead of the more specific "wiretapping". The public hearing is the first of several that the intelligence committees are expected to hold on Russia's interference in the election. It does not say whether the surveillance targeted Russians or Americans.
Rep. Devin Nunes, R-Calif., chairman of the House Permanent Select Committee on Intelligence, answers questions at the U.S. Capitol during a press conference on March 7.