Joe Biden, former Rep. Gabby Giffords blame Congress for not acting on gun violence

— -- Standing next to his wife former Arizona Congresswoman Gabrielle Giffords, retired NASA astronaut Cpt. Mark Kelly called today a "dark day for our country" after the Las Vegas shooting and called on Congress to take action on gun control.

Kelly lamented the Las Vegas shooting, which left at least 58 dead and 515 injured, as another incident that has altered the lives of many people.

"They’re not alone," Kelly said at a news conference outside the U.S. Capitol. "This is the worst case scenario. It’s haunted our dreams."

"This was an ambush if there ever was one," he said. "This was domestic terrorism."

While Kelly said he and Giffords are praying for the victims, he criticized Congress for not acting.

Kelly and Giffords co-founded the gun violence prevention organization Americans for Responsible Solutions after Giffords suffered a gunshot to her head at a constituent meeting in a supermarket parking lot on Jan. 8, 2011 in Tucson.

"Your thoughts and prayers are not going to stop the next shooting," he said. "Only action and leadership will do that."

Kelly emphasized that the massacre in Las Vegas could have been even worse if the shooter had a silencer, or if victims were armed and returning fire.

"We do not have to live this way," he said. "It’s an epidemic that needs to be cured."

He derided Trump's response to the incident, in which he offered prayers for the victims of the Las Vegas shooting, saying the country needs more; a concrete plan.

"We need a president that recognizes we have a gun violence problem and will work towards a solution," Kelly said. "Public safety must be your top priority."

The retired NASA astronaut blamed the "polarization of our politics" and the powerful corporate lobby for preventing consensus on gun regulations in Congress.

"Right now they’re going in the wrong direction," Kelly said. "What it takes is people that put these folks in office to take action."

Asked if he was politicizing the Vegas shooting, Kelly asked, "If not now, when? Today is the time."

"The nation's counting on you," Giffords said, turning to face the Capitol and holding up her fist.

"I am praying they find the courage it will take to make progress on the challenging issue of gun violence," Giffords said in statement to her former colleagues on the Hill. "I know they got into politics for the same reason I did -- to make a difference, to get things done. Now is the time to take positive action to keep America safer. Do not wait."

White House press secretary Sarah Sanders said that the focus today should be on the victims of the shooting and their families.

"There will be certainly time for that policy discussion to take place, but that's not the place that we're in at this moment," said Sanders.

"A motive is yet to be determined and it would be premature for us to discuss policy when we don't fully know all of the facts or what took place last night," she added.

Sen. Chris Murphy, D-Conn., echoed Kelly's sentiments saying, "It's time for Congress to get off its a-- and do something."

Former Vice President Joe Biden agreed that immediate action should be taken, calling on Congress and the White House to "act now to save lives."

Former President Barack Obama said he and former first lady Michelle Obama's prayers are with the victims and their families.