An RSA SecurID key fob.

Hackers have broken into the computer systems of Lockheed Martin and other major U.S. weapons manufacturers, potentially gaining access to information about future weapons programs as well as military technology currently in use, according to a Reuters report.

In an early report, the news agency cited a defense official and "two sources familiar with the issue." It has since said that it's unclear what--if any--data had been stolen.

A Lockheed representative told The Wall Street Journal, which cited its own unnamed source, that the company wouldn't comment on any specific incident but that "we have policies and procedures in place to mitigate the cyberthreats to our business, and we remain confident in the integrity of our robust, multilayered information systems security."

The intrusion could be related to the recent breach of RSA's popular SecurID token authentication technology, according to various news reports. SecurID is used in electronic "keys" company employees and others rely on to securely access computer networks. The Journal said remote access to some Lockheed networks was temporarily disabled and that Lockheed had sent 90,000 replacement keys to workers and asked employees to change all their company-related passwords as a safeguard.

Industry officials have said weapons contractors are unlikely to keep truly sensitive data on networks that can be accessed remotely, The New York Times reported.

Tech blogger Robert Cringely said the network disruption at Lockheed began Sunday and that the SecurID tokens were at the center of things, according to Reuters. The news agency also said that RSA-parent EMC had declined to comment on the issue, and that other defense contractors were, like Lockheed, remaining mum on the incident.

Lockheed makes a plethora of weapons and military technologies, from missiles to fighter planes to satellite-based field communications systems. RSA's SecurID technology is also used by the Pentagon, as well as other government agencies and numerous financial institutions.

On announcing the breach of the SecurID technology, in March, RSA said, "While at this time we are confident that the information extracted does not enable a successful direct attack on any of our RSA SecurID customers, this information could potentially be used to reduce the effectiveness of a current two-factor authentication implementation as part of a broader attack. We are very actively communicating this situation to RSA customers and providing immediate steps for them to take to strengthen their SecurID implementations."

The New York Times reported that military contractor Raytheon said Friday that it took "immediate companywide actions" when the RSA breach was made known and that it had, as a result, "prevented a widespread disruption of our network." The Times also reported that General Dynamics said it hadn't experienced any issues related to the SecurID breach but that other major military contractors, including Northrop Grumman and Boeing, had declined to comment.

Update, 6:45 p.m. PT: Reuters reported late today that the Department of Homeland Security told the news agency it had offered, along with the Defense Department, to help determine the extent of a "cyber incident impacting LMCO," or Lockheed Martin.