The Information Center for Human Rights and Democracy, a Hong Kong- based organization that frequently exposes human rights abuses in China, said in a statement the authorities only revealed situations at sites that store civilian-grade nuclear materials, but they neglected military nuclear sites.

"Sichuan is the province most heavily used for nuclear studies and military nuclear industrial development," the center said. "If these nuclear sources were damaged, the destructive force it released would be hundreds of thousands times more powerful."

The center said the authorities have remained tightlipped about whether any military nuclear source was damaged in the magnitude 8 quake that hit a vast area of the province on May 12.

Nearly 69,000 people were killed in the quake and some 18,600 remain unaccounted for.

About five million people were made homeless.

The center said the military has stored an unidentified amount of nuclear warheads and set up nuclear missile launch sites in the province, in addition to a massive number of nuclear factories and institutes that process radioactive materials.

The Environmental Protection Ministry said last week that 15 radiation sources were still inaccessible.

The center said the 15 sources were for civilian use such as cement factories, but none of the military nuclear sources, which are managed under the Central Military Commission, were mentioned.