The top two senators on the intelligence committee say they have seen no indication that Trump Tower was "the subject of surveillance" by the US government before or after the 2016 election.
President Donald Trump accused former President Barack Obama of wiretapping him and asked congressional committees investigating Russia's interference in the election to pursue that as well.
Republican Sen Richard Burr and Democratic Sen Mark Warner issued a joint one-sentence statement and did not elaborate.
The two senators are leading one of three congressional investigations into Russia and the presidential election.
The probes include looking into Trump associates' contacts with the Kremlin.
In response to Mr Trump's claims, the Justice Department is doing its own review of whether the president or any of his associates were the subject of surveillance.
President Donald Trump has unveiled a 1.15 trillion dollar budget, a far-reaching overhaul of federal government spending that slashes many domestic programmes to finance a significant increase in the military and make a down payment on a US-Mexico border wall.