WASHINGTON: Six international powers are counting on unity to check Iran’s nuclear ambitions, according to a European diplomat who expects China to drop its opposition to new sanctions for fear of isolation.

As Iran balks at a confidence-building proposal, the five permanent members of the UN Security Council — the United States, Russia, China, France, and Britain — plus Germany are increasingly weighing sanctions.

The negotiating group, known as the P5-plus-1, looks likely to head back to the United Nations.

“The unity of the P5-plus-1 is our major asset, our major aim,” a high-ranking European diplomat said on the condition of anonymity.

“I’m not saying it’s easy, but I’m confident we’ll get to the Security Council,” according to the diplomat who is close to the talks on Iran.

The P5-plus-1 has been reaching out to Iran in a bid to force the regime to halt its uranium enrichment.

But Iran has long equivocated in response to an offer from the Vienna-based UN International Atomic Energy Agency (IAEA) to ship abroad low-grade nuclear fuel so it can be further enriched and returned to refuel a Tehran medical research reactor.

In Vienna, diplomats said yesterday the Islamic Republic had effectively rejected the deal because it refused to accept some of the conditions called for by the West and insisted on a simultaneous exchange of fuel.

Western countries have ruled out such an exchange as unacceptable.

The proposal made by the IAEA last October, “which was supported by France, Russia and the United States, continues to be on the table,” said IAEA spokeswoman, Gill Tudor.