California governor signs law to limit shootings by police

California is changing its standards for when police can kill under a law signed by Governor Gavin Newsom, as it tries to deter police shootings of young minority men that have roiled the nation.

"We are doing something today that stretches the boundary of possibility and sends a message to people all across this country that they can do more and they can do better to meet this moment," Newsom said on Monday as he stood alongside family members of people killed by police.

The law by Democratic Assemblywoman Shirley Weber of San Diego will allow police to use lethal force only when necessary to defend against an imminent threat of death or serious injury to officers or bystanders.

But lawmakers dropped an explicit definition of "necessary" that previously had said officers could use deadly force only when there is "no reasonable alternative."