Apple Inc. said it has never worked with the U.S. National Security Agency to provide backdoor access to any of its products, including the iPhone.

Apple issued a statement Tuesday, following claims by researcher Jacob Appelbaum that the NSA gathers data from iPhones, including text messages, contact lists, voicemails and location data.

“We have been unaware of this alleged NSA program targeting our products,” said Kristin Huguet, a spokeswoman for Apple. “We will continue to use our resources to stay ahead of malicious hackers and defend our customers from security attacks, regardless of who’s behind them.”

Appelbaum, an independent researcher, said at a conference Monday in Germany that an NSA program called DROPOUTJEEP was tapping into Apple’s data. His comments followed a report by German news organization Der Siegel that detailed the spy agency’s ability to access data on smartphones.

The Der Spiegel report said the NSA has penetrated products from U.S. technology companies including Cisco Systems Inc. and Dell Inc. Cisco, the world’s biggest maker of computer-networking equipment, issued a statement on Dec. 29 saying that it’s “deeply concerned” about the government agency’s attempts to exploit technical weaknesses in its products to gather electronic communication data.

“At this time, we do not know of any new product vulnerabilities, and will continue to pursue all avenues to determine if we need to address any new issues,” Cisco said on its website. “If we learn of a security weakness in any of our products, we will immediately address it.”

Apple, Facebook Inc., Google Inc. and Yahoo! Inc. were among a group of technology companies that asked President Barack Obama on Dec. 17 to restrain spy programs exposed by former NSA contractor Edward Snowden in June and let them disclose the extent of government prying into their data. (Bloomberg)