"We're supporting their membership," a spokesman of the United States' State Department said.

"They are a significant nuclear supplier, have a good enough non-proliferation record and have made significant improvements in exports controls on nuclear and dual-use items," he said.

While the State Department moderates backed the move, some U.S. hard-liners, including Undersecretary of State John Bolton and the Pentagon, opposed it on allegation that China providing nuclear reactors to Pakistan, U.S. officials said.

China has helped Islamabad construct a 300 megawatt nuclear power reactor at Chasma, Pakistan. Last week, China and Pakistan agreed on a second Chinese reactor at Chasma, with Pakistan promising that the reactors would be peaceful and the technology would not be transferred to a third party without China's consent.

The Nuclear Suppliers Group (NSG), established in 1976, controls exports of equipment and materials that can be used to make nuclear weapons.

Guidelines require members to withhold certain nuclear transfers "when there is an unacceptable risk of diversion to such (nuclear weapons) activity."

The NSG last year invited China to apply for membership and Beijing did so. Now the group, including France, Britain, United States and Russia, is deciding whether to let the bid be approved by consensus.

Evan Medeiros of the RAND Corp, said the U.S. decision is "a well thought through effort to recognize China's real progress (on nuclear issues) and encourage further results in more troublesome areas of proliferation like missile exports."