By Fredrik Dahl
VIENNA (Reuters) - Western nations pressed China at closed-door nuclear talks to provide more information and help address concerns about its plans to expand an atomic energy plant in Pakistan, diplomatic sources said on Wednesday.
But China showed no sign of reconsidering its position on building two more reactors at the Chashma nuclear power complex in Pakistan's Punjab region, said the sources who attended a June 23-24 meeting of the Nuclear Suppliers Group (NSG).
Beijing's nuclear ties with Islamabad have caused unease in Washington, Delhi and other capitals. They are worried about Pakistan's history of spreading nuclear arms technology and the integrity of international non-proliferation rules.
Washington and other governments have said China should seek approval for the planned reactors from the NSG, a 46-nation, consensus-based cartel that seeks to ensure nuclear exports do not get used for military purposes.
Beijing is likely to shun such calls, arguing that the construction of two additional units at Chashma would be part of a bilateral deal sealed before it joined the NSG in 2004. China also supplied the facility's first two reactors.
The United States and European countries made statements at the meeting in the Dutch town of Noordwijk that "both expressed concern and asked the Chinese to provide more information," one diplomat who attended the talks said.
"The Chinese came back and said that as far as they were concerned Chashma 3 and 4 came under the agreement that was grandfathered when they joined in 2004 and that is as far as they feel they need to go," the diplomat added.
The NSG's annual plenary session addressed a range of nuclear-related issues, and agreed to tighten guidelines for the transfer of sensitive enrichment and reprocessing technology that can be used to develop nuclear weapons.
But a statement about the talks did not mention Chashma.
"It is a very sensitive topic," said one European official.
Another diplomat who declined to be named said: "A number of countries expressed concern and requested more information. There was a brief response from China."
Close relations between China and Pakistan reflect a long-standing shared wariness of their common neighbor, India, and a desire to hedge against U.S. influence across the region.
Chinese nuclear companies have not issued detailed information about when they will start building the new units, but contracts have been signed and financing is being secured.
To receive nuclear exports, nations that are not one of the five officially recognized atomic weapons states must usually place all their nuclear activities under the safeguards of the U.N. International Atomic Energy Agency, NSG rules say.
When the United States sealed a nuclear supply deal with India in 2008 that China and other countries found questionable because Delhi -- like Islamabad -- is outside the nuclear Non-Proliferation Treaty (NPT), Washington won a waiver from that rule after contentious negotiations.
Pakistan wants a similar civilian nuclear agreement with the United States to help meet its growing energy needs.
But Washington is reluctant, largely because a Pakistani nuclear scientist, Abdul Qadeer Khan, admitted in 2004 to transferring nuclear secrets to North Korea, Iran and Iraq.
Pakistan tested nuclear devices in 1998, soon after India, and both nations refuse to join the NPT, which would oblige them to scrap nuclear weapons.
The first diplomat suggested that a possible way forward on Chashma was if China said that the two new reactors would be the last it claims do not need approval from the NSG.
"What in reality is needed is something that says: this is it, this is the end. And if Chashma 3 and 4 are the end, that is possibly a price worth paying," the diplomat said.
Nuclear analyst Mark Hibbs said he believed China would press ahead with its Pakistan reactor plans and that there were divisions among other NSG states on how to respond to this.
"A kind of 'don't ask, don't tell policy' ... would be very damaging for the credibility of the NSG," said Hibbs, of the Carnegie Endowment for International Peace.
(Editing by Mark Heinrich)