President Trump promised a smooth transition in a video message posted on Twitter Thursday night, saying that his supporters had pursued post-election challenges in good faith, but “now tempers must be cooled and calm restored.”

Trump’s comments are the closest he has come to acknowledging his loss, and they follow escalating calls for his removal, coming hours after the nation’s top congressional Democrats demanded he be removed from office for his role in the deadly sacking of the U.S. Capitol by a pro-Trump mob.

House Speaker Nancy Pelosi (D-Calif.) and Senate Minority Leader Charles E. Schumer (D-N.Y.) called on officials to immediately invoke the 25th Amendment, warning that they are prepared to begin impeachment proceedings if the Cabinet and vice president do not act.

Though that extraordinary step is unlikely to succeed, it is a sign that a growing number of Democrats and Republicans now believe Trump is too dangerous to remain president.

Trump “invited an armed insurrection against the United States of America,” Pelosi told reporters a day after a pro-Trump mob incited by the president stormed the Capitol, vandalizing the building and forcing lawmakers to evacuate. One woman was fatally shot and three people died of other causes.