Italy's Hacking Team, which makes surveillance software used by governments to police the web, appeared to be the victim of hacking on a grand scale itself on Monday.
The Milan-based company, which describes itself as a maker of lawful interception software used by police and intelligence services worldwide, has been accused by anti-surveillance campaigners of selling snooping tools to governments with poor human rights records.
Hacking Team's Twitter account was hijacked on Monday and used by hackers to release what is alleged to be more than 400 gigabytes of the company's internal documents, email correspondence, employee passwords and the underlying source code of its products.
"Since we have nothing to hide, we're publishing all our emails, files and source code," posts published on the company's hijacked Twitter account said. The tweets were subsequently deleted.
Company spokesman Eric Rabe confirmed the breach, adding that "law enforcement will investigate the illegal taking of proprietary company property."
Hacking Team customers include the U.S. FBI, according to internal documents published Monday. That agency did not immediately respond to a request for comment.
Among the documents published was a spreadsheet that purports to show the company's active and inactive clients at the end of 2014. Those listed included police agencies in several European countries, the U.S. Drug Enforcement Administration and police and state security organizations in countries with records of human rights abuses such as Egypt, Ethiopia, Kazakhstan, Morocco, Nigeria, Saudi Arabia and Sudan.