Social networking giant Facebook is working with the FBI to investigate a malware attack, a report has said.
Investigators have not found any evidence that user data was compromised, Facebook said on its website.
The malware infected laptops used by Facebook employees when they visited a mobile developer's website, the company said.
The attack affected other companies, Facebook said, without identifying them, the Sydney Morning Herald reports.
It is collaborating on the attack through an informal working group.
The company said it is 'working continuously and closely with own internal engineering teams, with security teams at other companies, and with law enforcement authorities to learn everything we can about the attack, and how to prevent similar incidents'.