US lawmakers from both parties said today they had seen no proof to support the claim by Republican President Donald Trump that his predecessor Barack Obama had wiretapped him last year. This has added pressure on Trump to explain or back off his repeated assertion.<br/><br/>Several Republicans last week urged Trump to apologize for the allegations he made in a series of tweets on March 4. The maelstrom also caused tension with key US allies and threatens to distract Republicans from campaign promises on health care and taxes.<br/><br/>FBI Director James Comey is expected to be asked about Trump's claims when he testifies at a rare public hearing on Monday about alleged Russian meddling in the 2016 presidential election.<br/><br/>Russia has denied the assertion it was involved in hacked emails and other attempts to influence the race.<br/>