Chinese hackers, intent on gathering intelligence on the United States, gained access to government email inboxes. This was reported by Microsoft, writes The New York Times.

The attack was targeted, the person said, with hackers targeting specific accounts rather than a large-scale intrusion. White House National Security Council spokesman Adam Hodge said no classified networks were affected. The amount of stolen information is being assessed.

Microsoft said a total of about 25 organizations, including government agencies, were compromised by a hacking group that used forged authentication tokens to gain access to individual email inboxes. Hackers had access to at least some accounts for a month before the breach was discovered. The company did not say which organizations and departments were affected by the attack.

Its style and character suggest that the Chinese hacking group was either part of or working for Beijing’s intelligence service.

“We assess this adversary is focused on espionage, such as gaining access to email systems for intelligence collection,” Microsoft executive vice president Charlie Bell wrote in a blog post.

It was previously reported that hackers suspected of working for russian foreign intelligence targeted dozens of diplomats at embassies in Ukraine with a fake used car sales ad, trying to hack into their computers.