An elaborate China-based online spying network has used several social networks to hack government computers around the world.

Researchers at the University of Toronto's Citizen Lab say the cyber spies used services such as Twitter, Google Groups and Yahoo! Mail. The lab says the spies attacked government, business, academic and other computer networks in India, the Offices of the Dalai Lama, the United Nations, and several other countries.

Data stolen from dozens of hacked computers mostly in India contained sensitive information about missile systems and artillery designs, Sino-Indian relations, as well as personal, financial and business information of citizens from 31 countries.

The lab says state spies or criminal groups are aiming to sell the information to governments. The researchers speak of a new market.

The Canadian researchers traced the cyber attacks to servers in Chengdu, China, but could not identify the culprits. China has denied any involvement in the attacks cited in the Citizen Lab report.

The news comes just weeks after Internet giant Google effectively shut down its China search engine over censorship and cyber attacks.