Cybersecurity firm FireEye said Tuesday it had been hacked by what the company called “a nation with top-tier offensive capabilities," compromising its internal software and systems, the Wall Street Journal reports.

Why it matters: The company said the attacker accessed the firm's internal tools used to test the cyber defenses of its clients and sought information about its government customers. FireEye noted it had no evidence thus far that data belonging to its clientele had been jeopardized, and is investigating the breach with the help of the FBI and industry partners, such as Microsoft.