Smartphone thefts soaring in the United States

In the tech-savvy city of San Francisco - teeming with commuters and tourists - the cellphone is a top target of robbers who use stealth, force and sometimes guns.

Nearly half of all robberies in the city this year are cellphone-related, police say, and most happen on crowded trains and buses.

One thief snatched a smartphone while sitting right behind his unsuspecting victim and darted out the rear of a bus in mere seconds.

Another robber grabbed an iPhone from an oblivious bus passenger - while she was still talking.

In nearby Oakland, city council candidate Dan Kalb was robbed at gunpoint of his iPhone last Wednesday after he attended a neighbourhood anti-crime meeting.

"I thought he was going to shoot me," said Kalb, who dropped his phone during the holdup. "He kept saying, 'Find the phone, find the phone.'"

The brazen incidents are part of a crime wave striking coast to coast. New York police report that more than 40 per cent of all robberies now involve cellphones. And cellphone thefts in Los Angeles, which account for more than a quarter of all the city's robberies, are up 27 per cent from this time a year ago, police said.