Trump Says He Is Willing to Testify Under Oath in Mueller Probe

President’s remarks seemed to surprise White House aides; lawyers working out details for interview

Mr. Trump’s attorneys have been considering whether Mr. Trump should take questions from Mr. Mueller, according to a person familiar with the matter. They have debated whether Mr. Trump should answer questions from Mr. Mueller in writing, have Mr. Trump appear before Mr. Mueller in person, or perhaps a combination of the two, the person said. Another possibility Mr. Trump’s attorneys have been considering is letting Mr. Trump sit for certain topics, but not others.