WASHINGTON—Democratic leaders sought to tamp down calls for impeachment proceedings against President Trump, saying they are premature and risky, after video of a freshman congresswoman’s salty remarks about removing him from office reignited the debate within the party.

Speaking late Thursday to supporters, Rep. Rashida Tlaib (D., Mich.), said of Mr. Trump: “We’re gonna go in there and we’re gonna impeach the motherf—er.” On Friday, she stood by her remarks, tweeting: “I will always speak truth to power. #unapologeticallyMe,” but declined to comment further to reporters at the Capitol.

Ms. Tlaib, one of the first Muslim women elected to Congress, also co-wrote an op-ed on Thursday in the Detroit Free Press calling for impeachment hearings to begin immediately, before the conclusion of special counsel Robert Mueller’s investigation into the Trump campaign over collusion with Russia and obstruction of justice.

Mr. Trump, who has called the Mueller probe a “witch hunt” and denied wrongdoing, told reporters at the White House on Friday that the congresswoman’s remarks were “disgraceful” and objected to her use of profane language.

Mr. Trump uses profanity in private and occasionally in public. Earlier in the day, he brought up the episode in a closed-door meeting with congressional leaders at the White House, using some of the same expletives, people familiar with the matter said.