Former Vice President Joe Biden called for Congress and the White House to enact gun control legislation after a gunman killed more than 50 people and wounded at least 500 others at a country music festival in Las Vegas on Sunday night, and said there is "no excuse for inaction."

"Appalled by the senseless loss of life in Las Vegas. Jill and I hold all those affected and grieving in our hearts," Biden tweeted Monday. "How long do we let gun violence tear families apart? Enough. Congress & the WH should act now to save lives. There's no excuse for inaction."

Biden joined a growing chorus of Democrats pushing for Congress to pass gun control legislation in the wake of Sunday night's shooting.

Hillary Clinton emboldened lawmakers to "stand up to the NRA," and said members of Congress should oppose efforts to make it easier to buy gun suppressors, which the NRA supports.

Sen. Chris Murphy, D-Conn., said Congress needs to "get off its ass and do something."

Stephen Paddock, 64, opened fire on attendees of the Route 91 Harvest country music festival Sunday night. He fired down at concert-goers from a hotel room on the 32nd floor of the Mandalay Bay Hotel and Casino.

Paddock is believed to have killed himself before law enforcement broke into the hotel room, which he had been in since Sept. 28.

When police searched the room, they found at least 10 rifles, Las Vegas Metropolitan Police Sheriff Joseph Lombardo said.