US calls for Russian, Chinese nuclear transparency

The United States called for more transparency Wednesday as it accused Russia and China of not fully reporting their nuclear programmes amid US threats to withdraw from a key arms control treaty.

A senior US official made the remarks as the five permanent members of the UN Security Council -- all of them nuclear-armed powers -- met in Beijing for talks on nuclear disarmament and non-proliferation.

Andrea Thompson, US under secretary for arms control and international security, said there were "uneven results" in efforts to advance transparency under the nuclear non-proliferation treaty.

"We previously agreed to set (a) format for reporting, but the gap between the reports of the United States on the one hand, and Russia and China on the other, is great," Thompson said in her opening remarks.

"I cannot overemphasise the value of transparency," she said.

"We look forward to discussing how we can enhance transparency with a view to reassuring others of the very real steps we are taking to ensure full and verifiable compliance with our arms control non-proliferation and disarmament commitments and obligations."