WASHINGTON — The F.B.I. director, James B. Comey, asked the Justice Department this weekend to publicly reject President Trump’s assertion that President Barack Obama ordered the tapping of Mr. Trump’s phones, senior American officials said on Sunday. Mr. Comey has argued that the highly charged claim is false and must be corrected, they said, but the department has not released any such statement. Mr. Comey made the request on Saturday after Mr. Trump leveled his allegation on Twitter. Mr. Comey has been working to get the Justice Department to knock down Mr. Trump’s claim because there is no evidence to...