China and Russia are holding back from a united message with Western powers to insist that Tehran halt uranium enrichment, a stance that could encourage Iranian defiance, diplomats said Monday.

Speaking outside a meeting of the International Atomic Energy Agency's 35-nation board, the diplomats told The Associated Press that China was opposed to signing a joint statement and Russia was leaning against participating.

Head of the Chinese delegation Qin Sun waits for the start of a meeting of the 35-nation board members of the International Atomic Energy Agency (IAEA) at Vienna's International Center, on Monday, June 12, 2006. The meeting is overshadowed by the standoff over Iran's uranium enrichment program. [AP]

Their reluctance reflected the East-West divide among the six world powers that just two weeks ago appeared to be in agreement about how to engage Iran over enrichment and to persuade it to give up technology that could be used to make nuclear arms. Iran says its program has the sole purpose of generating electricity.

"China is not OK and Russia might follow" Beijing's lead in opposing the joint statement, said a diplomat accredited to the meeting, who like other diplomats agreed to discuss the issue only if not quoted by name because the information was confidential.

Another diplomat said China appeared to be feeling pressure from the Nonaligned Movement, which last month emphatically backed Iran in its nuclear standoff with the West.

Russia's stance was less clear. But Moscow for months has hindered attempts by the United States and its European allies to turn up the heat on Iran in the U.N. Security Council.

Resistance by Russia and China to tough U.N. action contributed to Washington's decision last month to reverse decades of policy and agree to join in multinational talks with Iran ¡ª if Tehran accepts a package of rewards, freezes enrichment during the talks and places a long-term moratorium on such activity.

British Foreign Secretary Margaret Beckett announced at the end of high-level talks in Vienna on June 2 that all five permanent Security Council members plus Germany supported the joint approach on engaging Iran.

But the signs of discord Monday reflected continuing differences despite the public show of unity.

One diplomat said Britain, France and Germany ¡ª the three European nations participating in the six-nation Iran package ¡ª were modifying a draft statement on Iran hoping to secure Moscow's and Beijing's backing on a final version.

Other diplomats spoke of more potential divisions. China, Russia and possibly Germany might push to allow Iran some tightly controlled small-scale enrichment rather than see talks founder. Russia and China also might balk at enforcing selective U.N. sanctions on Iranian officials and activities.

But long-term, verifiable suspension of Iranian enrichment is a "red line" for the United States and its key Western allies, one diplomat said.

While the IAEA meeting is not expected to formally focus on the Iranian nuclear standoff until Wednesday at the earliest, the issue dominated the gathering on its first day Monday.

IAEA chief Mohamed ElBaradei told the meeting his agency had not made much progress in resolving verification issues with Iran, alluding to suspicions that some of Tehran's nuclear activities could be used for the development of an atomic weapons program.

He described the rewards offered to entice the Tehran regime into negotiations as addressing "the need of the international community to establish confidence in the exclusively peaceful nature of Iran's nuclear program."

Chief U.S. delegate Gregory L. Schulte called on Iran to respond positively to the offer for talks ¡ª and suspend enrichment, which can be used both to produce fuel for nuclear reactors that generate power and to create the core of atomic warheads.

"The next decision needs to be taken not in Vienna but in Tehran," Schulte told reporters.

In Luxembourg, the European Union's foreign policy chief, Javier Solana, said he expected an Iranian response to the six-power offer this week.

But Iran suggested it was digging in its heels on enrichment. When asked if Iran would suspend enrichment for the sake of negotiations, spokesman Gholam Hossein Elham repeated the government line that enrichment is Iran's "obvious right."