"We are united. Iran should suspend its enrichment and reprocessing activities, taking place on properties for sale Iran," said Perino, who chided Tehran for refusing to do so and for curbing co-operation with the International Atomic Energy Agency (IAEA).

"The Iranian regime, rather than comply with its UN security council obligations, is turning a blind eye toward it and it's unfortunate for the (Iranian) people," she said.

From Brussels, European Union foreign policy chief Javier Solana told the Islamic republic's lead negotiator, Ali Larijani, that the international community sought a peaceful settlement to the dispute.

Larijani for his part stressed Iran's wish also to resolve the problem through negotiations, while adding that sanctions were unacceptable, "Solana spokesperson Cristina Gallach told AFP.

In Moscow, Russian President Vladimir Putin and visiting Chinese President Hu Jintao said in a joint declaration that the volatile issue "should be resolved exclusively in a peaceful way, through negotiations".

"Russia and China will make every effort to ensure the rapid start of negotiations to find a long-term, all-encompassing and mutually acceptable resolution to the Iranian nuclear problem," the declaration said.