Apple on Wednesday denied claims that it had worked with the government to share millions of device identification numbers, a day after the hacking group known as AntiSec claimed to have obtained numbers from an F.B.I. laptop.

In a statement, Apple said it had not worked with the Federal Bureau of Investigation or any other agency to release the numbers, called unique device identifiers or U.D.I.D. numbers.

“The F.B.I. has not requested this information from Apple, nor have we provided it to the F.B.I. or any organization,” said Natalie Kerris, an Apple spokeswoman. “Additionally, with iOS 6, we introduced a new set of A.P.I.’s meant to replace the use of the U.D.I.D. and will soon be banning the use of U.D.I.D.”

Apple’s unique device identifiers are 40-character strings of letters and numbers assigned to Apple devices that act as fingerprints for the company’s mobile devices.

On Tuesday, the F.B.I. denied that the identification numbers had been taken from the agency. It noted in a statement that there was “no evidence indicating that an F.B.I. laptop was compromised or that the F.B.I. either sought or obtained this data.”

Antisec, a subset of the loose hacking collective Anonymous, claimed to have obtained 12 million numbers for iPhone, iPad and iPod Touch devices, and some phone numbers and other personal data on the owners of the devices.