WASHINGTON (AP) — Jill Biden, a lifelong teacher who recently mourned the 21 pupils and teachers killed at a Texas elementary school, issued a passionate call on Friday for parents and teachers to "speak up" and demand that Congress pass "common sense" gun safety measures.

"There are no excuses. It's up to Congress to act," the first lady said in a speech to the National PTA Convention meeting in a Maryland suburb of Washington. "And they represent the will of the people and that's why we need the people to speak up. Parents and teachers, all of us."

"We need to fight, now, for the lives of our children and for the safety of our schools," she said.

The first lady, who has taught for nearly 40 years and teaches English and writing at Northern Virginia Community College, acknowledged that "I've wondered over the years if my students would be the next heartbreaking headline."

She said she often imagines the terrifying scene of a school shooter playing out in her own classroom, and described how she explains to her students on the first day of class how they can escape "if the worst happens."

"So Congress did not act after Columbine, after Sandy Hook, after Parkland," Jill Biden said, referencing some of the deadliest school shootings in U.S. history. "Nothing changed, and nothing will change unless we change it."

The first lady echoed top advisers to her husband, who say President Joe Biden has milked his executive authority to address gun violence and that next steps are up to Congress.

President Biden has called for a range of gun safety measures, including reinstating a long-expired ban on the type of assault-style weapons that were used in the New York and Texas shootings.

A group of Democratic and Republican senators last weekend announced the elements of a compromise acceptable to both sides, minus the assault-weapons ban. The lawmakers have spent this week working to finalize a bill that can be voted on by a self-imposed early July deadline.

In brief remarks at the Parent Teacher Association convention, the first lady recalled her visit last month with the president to Robb Elementary School in Uvalde, Texas, where 19 pupils and two teachers in adjoining classrooms were gunned down by an 18-year-old male who was later killed by police.

She described touching the photos of the "bright, beautiful faces that would never again laugh or open birthday presents or tell their parents that they love them."

"And I laid down white roses on a sea of colorful flowers, the offerings of a town broken by grief, just as I had done in Buffalo, New York, one week before," the first lady said, referring to the couple's earlier visit to the scene of a racist attack on a supermarket that left 10 Black people dead.