Chinese authorities reportedly attacked Apple's iCloud storage to steal credentials such as user names and passwords. The alleged attack coincides with the launch of the new iPhones in the China, according to a blog posted on Monday by censorship-monitoring group GreatFire.org.

"This is clearly a malicious attack on Apple in an effort to gain access to user names and passwords and consequently all data stored on iCloud such as iMessages, photos, contacts, etc.," GreatFire.org wrote. "Unlike the recent attack on Google, this attack is nationwide and coincides with the launch today in China of the newest iPhone."

The hackers used fake Apple certificates to intercept the iCloud data traffic, according to GreatFire.org. The alleged attack is targeting U.S. servers, particularly those trying to access Apple.com through Google Chrome. A warning message was displayed on the page saying, "Your connection is not private," InformationWeek reported. Once user names and passwords are collected, the Chinese authorities might be using them to unlock encrypted data on iOS devices.

The group described the attack as a "man-in-the-middle" (MTM) attack which aims to modify the data supplied by the connection. This is not the first time that China has been accused of such activities; Chinese authorities allegedly recently launched an MTM attack against Yahoo to alter information related to the Hong Kong protests. Github and Google were previous victims, too.

"If true, it would seem to be a big deal, targeting even larger groups of people," Adam Segal, a Council on Foreign Relations expert on cybersecurity and China, told Mashable. "[It's] part of the trend of controlling and monitoring web services even more closely."

Other security experts are convinced that the Chinese government is behind the attack. Telecommunication providers or governments can only perform such attacks.

"All the evidence I've seen would support that this is a real attack. The Chinese government is directly attacking Chinese users of Apple's products," Mikko Hypponnen, chief research officer at security software developer F-Secure, told Reuters. "As always, we recommend using the Internet over a trusted virtual private network."

The Chinese embassy, Google, and Apple have not responded yet commented on the reports.