Story highlights President Donald Trump accused then-President Barack Obama of wiretapping him last year

Republicans on the Hill, charged with investigating the claim, say they've seen no evidence

(CNN) The top Republicans investigating Russia's interference in the US election declined Tuesday to back up President Donald Trump's claims that then-President Barack Obama wiretapped his Manhattan headquarters last year -- leaving the White House on its own to explain the stunning allegation.

When pressed on whether he believed Trump's allegations, House Intelligence Chairman Devin Nunes -- one of Trump's strongest supporters in the House and a member of his transition team -- brushed aside the President's allegations.

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"A lot of the things he says, you guys take literally," Nunes told reporters Tuesday. Nunes later hedged his comments and said that former National Security Adviser Michael Flynn may have been wiretapped and that Trump had raised "valid questions" about how his aides were listened in on.

Across the Capitol, Senate Intelligence Chairman Richard Burr, who is leading a concurrent investigation into Russia's interference, said he had not seen any evidence of Trump's claims.

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