Smartphones in California will be required to come with a "kill switch" to render them useless if stolen under a bill signed Monday by Governor Jerry Brown. The bill would be the strongest attempt yet by a U.S. state to fight smartphone theft.

"Our efforts will effectively wipe out the incentive to steal smartphones and curb this crime of convenience, which is fueling street crime and violence within our communities," said Democratic state Senator Mark Leno, the bill's author.

Under the new law all smartphones sold in the state after July 2015 will come pre-equipped with technology allowing them to be shut down remotely in the event of theft.