WASHINGTON — Education Secretary Betsy DeVos faced blistering questioning from House Democrats on Tuesday as they confronted her on gun control, among other issues.

DeVos’s testimony in front of the House Appropriations subcommittee got so tense that the chairman made a point of thanking DeVos for her poise when he concluded the meeting.

DeVos, already reeling after a series of rocky, high-profile interviews, unveiled some details of a federal commission on school safety that she will be chairing. The commission, formed after the Florida high school shooting in which 17 people were killed, will include the heads of the Homeland Security, Health and Human Services, and Justice departments.

DeVos said the commission will begin work in the next few weeks. A spokeswoman for DeVos later added that the panel will also involve students, teachers, law enforcement, and mental health professionals.

DeVos said the commission will, among other things, consider whether to ban gun sales to people under 21. President Trump initially spoke in favor of such a proposal but backtracked after meeting with representatives of the National Rifle Association. DeVos would not say whether she personally supports the idea.

DeVos also defended states’ and communities’ rights to decide whether to arm teachers.