People buying ammunition in California will soon have to be thumbprinted and dealers will have to keep records of sales, under legislation that Gov. Arnold Schwarzenegger signed into law.

After vetoing similar bills three times since 2004, Schwarzenegger signed AB962 by Assemblyman Kevin de León, D-Los Angeles, on Sunday, saying he now believes it will promote public safety.

The measure is California's first statewide regulation of ammunition sales. It survived close votes in both the Assembly and state Senate and strong opposition from gun-rights organizations, which succeeded in stripping a provision that would have required sellers of more than 50 rounds of ammunition a month to be licensed by the state.

Starting in July, the law will require dealers to keep records of handgun ammunition sales for at least five years, and store the bullets securely out of customers' reach.

Like gun transactions, all ammunition sales will have to be face-to-face, a requirement that will force online buyers to arrange delivery of ammunition to a seller in California. Another provision makes it a crime to knowingly sell or give ammunition to someone who cannot possess it legally, including felons, gang members and the mentally ill.

As of February 2011, all ammunition buyers will have to provide a driver's license or other state identification and a thumbprint.

De León said Monday that the bill gives police "a valuable tool to crack down on armed, dangerous criminals and gang-bangers in our communities."

Opponents said the restrictions would burden gun owners and dealers without impeding criminals.

"Ammunition or ammunition purchaser registration, in any form, serves only to infringe upon the rights of law-abiding citizens," Gun Owners of California said while the bill was before the Legislature.

In signing the bill, Schwarzenegger said local governments that require record-keeping for ammunition sales have enabled police to arrest many illegal purchasers. Governments that regulate ammunition sales include San Francisco, Oakland, Tiburon and Contra Costa and Marin counties.

"Utilized properly, this type of information is invaluable for keeping communities safe," Schwarzenegger said.