WASHINGTON (AP) -- The Latest on the congressional investigation into Russian hacking during the 2016 campaign and contacts between Trump campaign associates and Russian officials (all times local):
Republican Sen. Lindsey Graham says the FBI has promised members of the Senate Judiciary Committee a classified briefing soon to discuss whether there was any warrant issued to surveil any of Donald Trump's associates during the 2016 presidential campaign.
Graham says he has seen no evidence to support Trump's claim that the Obama administration wiretapped him last year.
Graham, of South Carolina, is leading one of three congressional investigations into Russia's interference in the 2016 election.
FBI Director James Comey was scheduled to brief top members of the Senate judiciary committee Wednesday afternoon in response to a separate request about the resignation of former National Security Adviser Michael Flynn and his contacts with Russian officials.
The leaders of the House Intelligence Committee are raising concerns about the disclosure of names of American citizens whose communications were caught up in U.S. surveillance of foreign agents.
Committee Chairman Devin Nunes and ranking member Adam Schiff say they're sending a letter to FBI Director James Comey, CIA Director Mike Pompeo and National Security Agency Director Mike Rogers. They say they're asking for the total number of Americans whose names were mentioned.
The lawmakers appear to be referring to former White House national security adviser Mike Flynn and potentially other associates of President Donald Trump. Conversations between Flynn and Russia's ambassador before inauguration were picked up by U.S. intelligence and later disclosed.
Identities of Americans who show up in U.S. surveillance against foreign entities are supposed to stay concealed.
The Republican and Democratic leaders of the House Intelligence Committee say they have seen no evidence supporting President Donald Trump's claim that the Obama administration wiretapped him last year.
GOP Rep. Devin Nunes and Democratic Rep. Adam Schiff say they're still waiting for evidence from the Justice Department backing up that claim. Schiff says he and Nunes are willing to take steps to compel the department to comply with their request if it refuses by the March 20 deadline they've given the Justice Department.
Nunes says he doesn't believe there was "an actual tap of Trump Tower" in New York.
Nunes also says the committee is tussling with the Office of the Director of National Intelligence over whether the committee will be allowed to have the computer technology needed to go through CIA evidence about Russia's interference in the election.
The leaders say FBI Director James Comey and the head of the National Security Agency will testify at a public hearing on March 20.
FBI Director James Comey will be briefing the top members of the Senate Judiciary Committee in response to their letter last month about the resignation of former National Security Adviser Michael Flynn and his contacts with Russian officials.
Sens. Chuck Grassley of Iowa and Dianne Feinstein of California sent a letter Feb. 15 to Attorney General Jeff Sessions and Comey asking about the circumstances that led to Flynn's resignation.
The two cited media reports that said both the FBI and Justice Department were involved, raising questions about the "content and context of Mr. Flynn's discussions with Russian officials."
Comey was slated to brief the senators Wednesday afternoon on Capitol Hill.
Longtime Trump adviser Roger Stone says he believes his contacts with a Russian-linked hacker who took credit for breaching the Democratic National Committee may have been obtained through a FISA warrant. That allows the government to collect the communications of individuals suspected of being agents of a foreign power.
Stone is among a handful of President Donald Trump's associates who are under scrutiny for possible links to Russia during the presidential race. In a statement to The Associated Press, Stone said he's retained two attorneys to explore whether he can compel the government to "either charge me or admit they have no case whatsoever."
The Republican operative has acknowledged having a Twitter exchange with Guccifer 2.0, a hacker that U.S. officials believe has ties to Russia. Stone said he was "unaware at the time of the brief exchange of allegations that the hacker in question is suspected of being a Russian asset."