NEW DELHI, NOVEMBER 3 In a signal of potential political trouble for Sino-Indian relations, the official Chinese media has launched a vicious attack on the Indo-US nuclear pact and warned of its ‘‘negative impact’’ on the global nuclear order.

At a time when the Left parties are accusing the government of selling out to the United States on the nuclear issue, the Renmin Ribao, China’s leading political daily, has charged the Bush Administration of being soft on India and undercutting the Nuclear Non-Proliferation Treaty.

As the government wakes up to this pincer attack, that comes precisely at a moment when India is poised to end its more than three decades long nuclear isolation, Beijing risks squandering its recently accumulated political good will in this country and rekindling forgotten hostilities.

Accusing the US of ‘‘double standards’’ on nuclear proliferation, the Renmin Ribao said if the US makes a ‘‘nuclear exception’’ for India, other powers could do the same with their friends and weaken the global non-proliferation regime.

‘‘Now that the United States buys another country in with nuclear technologies in defiance of international treaty, other nuclear suppliers also have their own partners of interest as well as good reasons to copy what the United States did,’’ Renmin Ribao said. (An English translation is available on the web at http://english.peopledaily.com.cn)

‘‘A domino effect of nuclear proliferation, once turned into reality, will definitely lead to global nuclear proliferation and competition,’’ the paper added. The Chinese criticism of the Indo-US nuclear pact is in contrast to the solid support for the deal from Russia, France, Britain, and Canada.

Analysing the change in US nuclear policy towards India, Renmin Ribao asked: ‘‘US acts leave people more and more dubious: is it striving to prevent nuclear proliferation or actively pushing in the opposite direction?’’

Reports from the Nuclear Suppliers Group meeting last month suggested China was among the few countries that critically questioned the US proposal to modify the global rules on nuclear commerce in favour of India.

‘‘Always calling itself a ‘guard’ for nuclear proliferation prevention, the United States often condemns other countries for irresponsible transfers but this time, it hesitates not a bit in revising laws, taking the lead in ‘making an exception’,’’ for India, Renmin Ribao said, warning ‘‘this will bring about a series of negative impacts.’’

Until now, the Chinese media has reported without comment the developments since July when Prime Minister Manmohan Singh and President George W.Bush signed the nuclear deal.

This is the first time official Chinese organs have mounted an attack against the deal, which treats India on par with other nuclear weapon powers in terms of access to civilian nuclear technology.

India might be willing to countenance the talk of nuclear ‘‘double standards’’ from the White Knights of the Western world like Sweden or Ireland. India, however, will be deeply troubled by at similar rhetoric from Beijing.

New Delhi which bitterly complained about China’s support to Pakistan’s nuclear weapons programme in the 1980s and Islamabad’s missile capabilities in the 1990s, will find it a bit rich if Beijing now opposes international civilian nuclear energy cooperation with India in the name of double standards.

India has been willing to overlook the extraordinary campaign by Beijing to defeat the attempt by the G-4, India, Japan, Germany, and Brazil, to expand the permanent membership of the UN Security Council earlier this year. China explained away this campaign by saying that the target was Japan and not India.

A similar campaign on denying the benefits of civilian nuclear energy cooperation to India could reopen New Delhi’s many past grievances against Beijing.

Until now India had assumed that nuclear differences with China that came to the surface after the Pokhran tests in 1998 had been set aside amidst rapidly improving Sino-Indian relations in recent years.