Trump attacks on fired FBI chief meet resistance; Russia probe proceeds

By Patricia Zengerle and Arshad MohammedWASHINGTON (Reuters) - President Donald Trump on Thursday ran into resistance for calling ousted FBI chief James Comey a "showboat," an attack that was swiftly contradicted by top U.S. senators and the acting FBI leader, who pledged that an investigation into possible Trump campaign ties to Russia would proceed with vigor.In his first interview since firing Comey on Tuesday, Trump appeared to try to underscore that Comey's dismissal was about his performan