The US, Britain and France warned Iran on Thursday that it may face new sanctions over its nuclear program, but Russia and China hinted that they were not convinced.

The Western powers have shown their desire to ratchet up the pressure on an increasingly defiant Teheran over its atomic ambitions during a UN Security Council debate on Iran. However Russia and China hinted that they were not convinced.

French UN Ambassador Gerard Araud told the council, “If it continues to refuse the slightest confidence measures, to refuse dialogue, transparency … we must draw all of the necessary conclusions and that means that we must move on to a new resolution involving sanctions.”

The French envoy later told reporters, “‘We make a last call to the Islamic Republic of Iran to respond to our offer of negotiation. ‘If Iran doesn’t do it on the short term, France will propose a new resolution of sanctions.”

Iran rejects the allegations, along with UN demands that it suspend a program it says is intended solely for the peaceful generation of electricity. But Western officials say recent revelations about a previously hidden uranium enrichment plant in Iran have made Teheran’s denials less credible.

Russia’s Foreign Ministry spokesman Andrei Nesterenko told reporters in Moscow, “This language of sanctions, it is not our language. It has already been said many times.” He further said Moscow favored ‘using political and diplomatic methods to resolve all emerging problems.’

The United States said again that Teheran might have to face new sanctions but did not touch on the question of when work on a new sanctions resolution should begin.

US Ambassador Susan Rice told the council, “Should Iran continue to fail to meet its obligations, the international community will have to consider further actions.”

The Chinese envoy stressed that China remained committed to negotiations with Teheran and there was still room for talks.

British Ambassador Mark Lyall Grant told reporters that the six powers would base a decision on whether to press for a new round of UN sanctions on an assessment of Teheran’s nuclear program and its response to their offer of economic and political incentives in exchange for an enrichment suspension.