Citing a surge in violent robberies, US authorities and cellphone carriers announced Tuesday an effort to crack down on smartphone theft.

The major carriers and the Federal Communications Commission answered rising pressure from US police departments with a plan for a national database for stolen phones that would prevent their use by new owners.

FCC Chairman Julius Genachowski said the four leading carriers had agreed to set up their own databases of stolen phones within six months, and aim for a common registry within 18 months, allowing those who lose their phones to prevent them from ever being used again.

"The numbers are alarming. In Washington DC, New York, and other major cities roughly 40 percent of all robberies now involve cellphones," Genachowski said.

"It endangers the physical safety of people all over the country, as well as the safety of personal information that is on the devices."

The aim is to allow phone users to easily report a stolen phone with carriers that will then refuse to activate it under a new owner -- rendering it unusable and worthless to thieves.

"What we are doing is drying up the market for stolen cellphones... as it has in Europe," said New York City's Police Commissioner Ray Kelly.

Police departments around the country have arrested hundreds of thieves and phone resellers in coordinated crackdowns on theft rings in recent months. Nearly all of the stolen phones, they said, are resold domestically.

But they say that the thefts are still surging and are growing more violent.

"I've got young ladies pushing baby strollers getting their jaws broken for a phone," said Cathy Lanier, Washington's police chief.

Charles Ramsey, Philadelphia's police commissioner, said that in his city: "These devices are being taken at the point of a gun, or they are being taken after a serious assault."

The new registry comes years after similar efforts have been carried out in Australia and Europe.

The London-based GSMA, a global association of more than 800 mobile operators, has also operated a counter-theft database based on phone serial numbers for years.

Christopher Guttman-McCabe of the industry's main trade group, CTIA-The Wireless Association, explained their sluggishness to take action as a consequence of the late rise in phone-related crime in the United States.

Cellphone thefts came much more slowly to the country because US carriers provide phones free or at hefty discounts to entice customers to commit to long-term service plans, he explained.

Genachowski said conversations with GSMA officials and British officials who operate their own registry convinced him the US could do the same.

He said the FCC will eventually push to integrate the US phone list with those of other countries to help stifle international trade in stolen phones.

"These are steps that will reduce the value of stolen smartphones and tablets," he said.

"We have called on all countries to adopt this database."