Hundreds of mothers and volunteers demanding action on gun control marched on the White House and the Capitol on the heels of the deadly shooting in El Paso, Texas on Saturday.

The founder of Moms Demand Action, Shannon Watts, said members of her organization -- which was created following the massacre in Newtown, Conn. in 2012 -- were teaming up with their sister activist group Students Demand Action.

Watts told the Associated Press they were demanding the U.S. Senate act on a background check bill for people wanting to buy a gun -- legislation which passed through the House of Representatives earlier this year.

The protesters chanted “Whose house? Our House!” and waved signs critical of passive lawmakers that read “Coward Congress.”

Students Demand Action is an initiative of Everytown for Gun Safety, which is a U.S. non-profit which was founded and largely funded by New York Mayor Michael Bloomberg in 2006.

The protest was one of several demonstrations across the country that day demanding similar action or support for the victims of gun violence.

The mom group’s volunteer leader Amber Gustafson said they had already arranged a national meeting in Washington, D.C.

But they decided to turn their efforts to marching on the White House when they heard about the shooting in El Paso on Saturday morning which left 20 dead and more than two dozen injured.

Gustafson said the protesters, who were clad in their traditional red t-shirts, often works at state and local levels but stressed that she is seeking a "federal remedy" to gun violence.

The suspected gunman in Texas, who reportedly has white nationalist views, was taken by authorities and is being held in custody.

The groups’ demonstration would take place mere hours before a second mass shooting in Dayton, Ohio early Sunday morning which left nine people dead and 26 other people injured.

The gunman in Dayton, who has not been identified by authorities, was shot to death by responding officers. Authorities have not identified a motive.

With files from The Associated Press