China has assisted Pakistan to build six nuclear reactors with a total installed capacity of 3.4 million kilowatts, a top Chinese official said on Sunday as Beijing plans to build two 1100 mw reactors in Karachi with USD 6.5 billion assistance.

Outlining China's nuclear technology exports, Wang Xiaotao, vice minister of the National Development and Reform Commission (NDRC), said the country is involved in initial discussions with several countries on the possibility of exporting its nuclear power equipment.

China is currently exporting nuclear technology to Pakistan and Argentina, he said. "China has assisted Pakistan to build six nuclear reactors to generate 3.4 million KW of power," he said, without giving details.

China has built two 300 MW reactors at Chasma in Pakistan's Punjab province followed by two 320 MW units at the same place. It has also announced plans to construct for the first time two 1100 MW reactors in Karachi.

India and the United States have expressed concern that the two reactors are being built without the sanction of the Nuclear Suppliers Group (NSG), which supervises the global civil nuclear technology commerce.

India had secured the NSG waiver in 2008 after the India-US civil nuclear deal. China signed a landmark deal with Argentina on Wednesday to build a pressurised water reactor (PWR) nuclear power plant there. "It did not take long for us from introducing this (nuclear) technology to exporting it," Wang said.