U.S. President Joe Biden wants Congress to pass tougher gun control policies following the latest mass shooting at a rail yard in Northern California in which eight people were killed, NBC News reported Thursday.

The U.S. flag over the White House was lowered to half-staff after the shooting just weeks after doing so in the wake of shootings in George, Colorado, South Carolina and Indiana. The president also issued a single-word plea: "Enough."

The gunman was identified as Samuel Cassidy, an employee of the Santa Clara Valley Transportation Authority.

He wounded several others, before killing himself. At least one victim remains in critical condition, Santa Clara County Sheriff's Office representative Russell Davis said.

Local authorities said they didn't know what the shooter's motive was.

California Gov. Gavin Newsom called for more gun control hours after the killings.

"What the hell is going on in the United States of America?" he asked, according to The Sacramento Bee.

"When are we going to put down our arms," the governor said as he called for the country to take gun violence seriously. 

Gun sales have set records and gun-related violence has increased in the U.S. over the past year.

According to a survey by the Pew Research Center, the public is divided on if an increase in the number of Americans who own firearms will result in more or less crime.

The survey shows 75% of Blacks, 72% of Asians and 65% of Hispanics say gun laws should be stricter compared with 45% of white people.

Meanwhile, David Chipman - Biden's pick to lead the Bureau of Alcohol, Tobacco, Firearms and Explosives - faced Republican criticism during his confirmation hearing Wednesday over his history of comments about gun ownership.

In an interview last year, Chipman, a 20-year veteran of the bureau, likened the buying of firearms during the coronavirus pandemic to a "zombie apocalypse."