Researchers at internet security company FireEye released a report on Monday revealing that hackers, who could have originated from China, have been spying on the internet networks of governments and businesses in Southeast Asia and India since 2005.

"The operations focused on targets - government and commercial - who hold key political, economic and military information about the region," Bryce Boland, Chief Technology Officer for Asia Pacific at FireEye and co-author of the report, wrote in the report.

"Such a sustained, planned development effort coupled with the (hacking) group's regional targets and mission, lead us to believe that this activity is state-sponsored - most likely the Chinese government," he wrote.

The researchers added that the operations are still ongoing. They weren't sure how big the team is, but they believe that at least two software developers are behind the cyber attack. Surprisingly, the operations remained undetected for years even though the hackers have been using the same method. The researchers explained that the hackers used phishing emails to install the malware to the targeted networks.

The group of cyber criminals, dubbed as APT30, targeted at least 15 companies in communications, technology, finance and aviation, aside from the government networks. Although there is no clear evidence that the hackers are working for the Chinese government, FireEye said that the software used by the team was developed in China, according to Bloomberg.

This is not the first time that China has been accused of employing hackers to target other countries. And as usual, the Chinese government firmly denied the allegations.

"I want to stress that the Chinese government resolutely bans and cracks down on any hacking acts. This position is clear and consistent. Hacking attacks are a joint problem faced by the international community and need to be dealt with cooperatively rather than via mutual censure," Chinese Foreign Ministry Spokesman Hong Lei told Reuters.