Hundreds of mothers surged to the White House with other protesters Saturday evening to demand stricter gun control laws in the wake of the horrific mass shooting in El Paso, Texas, that killed at least 22 people.

The powerful, spontaneous “Moms Demand Action” demonstration was one of a series of heartfelt expressions of support and sympathy throughout the nation for the victims of the shootings at a Walmart, in which at least 26 people were injured.

Mothers hoisted signs reading “Coward Congress” and chanted: “Whose house? Our house!”

A representative of the group told The Washington Post that members were meeting nearby for a conference. When the women learned of the massacre, “the tenor and tone of the whole room changed” and participants decided to march, said one of the group’s leaders, Amber Gustafson.

“We’re fed up. It’s past time for change,” she said.