In an event that appeared at least partly in response to Saturday’s mass shooting in El Paso, people marched to the White House and through Washington streets Saturday night to call for action against gun violence.

A leader of a group called Moms Demand Action said they were in Washington for an annual conference and were at a lunch when news about the Texas shootings arrived.

“The tenor and tone of the whole room changed,” said Amber Gustafson.

She said many young people had already planned to go to the White House, “and then this happened.”

Photos and videos posted online showed chanting demonstrators and marchers in Lafayette Square near the White House and then in a march, apparently to the Capitol. Moms Demand Action includes both men and woman, a spokeswoman said.

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

She said the group wanted the Senate to take up a House-passed measure to expand background checks for gun buyers.

“It’s time for action,” she said.

For at least a portion of the demonstration, Moms Demand Action spokeswomen estimated the size of the crowd as in the hundreds. At various points, including near the White House, and along 15th Street NW, and at the Capitol, a reporter’s observations, along with study of video footage and still photographs indicated the demonstration involved perhaps 250 to 350 people from both Moms Demand Action and Students Demand Action.