(CNN) -- As the United States steps up its push for tough new sanctions against Iran, a top American diplomat said Thursday that hopes of a deal with Iran to curb its nuclear ambitions are fading.
"What's happening is that Iran is headed in the direction of further provocation, further enrichment," U.S. Ambassador to the International Atomic Energy Agency Glyn Davies told CNN's Christiane Amanpour.
"They (Iran) refuse to take steps that are even in their own interest, if they're to be believed," he said. "So right now, what option do we have except to pursue sanctions in the U.N. context and work with our partners to try to bring this to a reality?"
In the same CNN broadcast, Iran's ambassador to the IAEA, Ali Asghar Soltanieh, told Amanpour that Tehran has opened a window for "face-saving," even as the U.S. and Europe pursue new United Nations sanctions against his country.
"They'd better reconsider this mistake, stop (the) involvement of the United Nations Security Council, come to the negotiating table on equal footing without precondition, and we are ready of course to remove any ambiguity," Soltanieh added.
Davies, though, said the world's patience with Iran is running out. "It's becoming quite clear that they're preserving at least the option of developing a nuclear program. And we want all nations of the world to take note of this and draw the right conclusion," he said.
"There really is only one way to go right now, only one way to focus Iran on the need to make different decisions, and that is by putting pressure on them."
Iran, however, insists its nuclear program is entirely for peaceful purposes.
The United States and its European allies are making a strong pitch to members of the U.N. Security Council for new sanctions that they say will be "smart and effective." Those proposed new sanctions reportedly would target Iran's banking, shipping, and insurance sectors.
But it's unclear if China, a veto-wielding member of the United Nations Security Council, will support the proposals.
"We believe there is still room for diplomatic efforts, and the parties concerned should intensify those efforts," Chinese Foreign Ministry spokesman Qin Gang said earlier this week.
Brazil, which currently has a rotating seat on the U.N. Security Council but no veto power, is also opposing sanctions against Tehran, despite a visit to Brasilia by U.S. Secretary of State Hillary Clinton on Wednesday.
Brazilian President Luiz Inacio Lula da Silva said, "It is not wise to push Iran into a corner. It is wise to establish negotiations."
Soltanieh told Amanpour he believes Russia also thinks the only way forward is talks, even though Russian President Dmitry Medvedev has indicated he's willing to consider sanctions.
"Today, (the) distinguished ambassador of Russia and distinguished ambassador of China (to the IAEA) clearly mentioned that they think that the only way is dialogue and negotiation, and this is the latest position that they have," Soltanieh added.
The Iranian diplomat said Tehran's offer of a simultaneous swap of low enriched uranium for fuel enriched to 20 percent from other countries is still on the table. He called it Iran's "maximum concession."
But Davies said the U.S. is seeing much more support for its position than previously at the IAEA after Iran's "failure" over eight years to comply with its obligations under the Non-Proliferation Treaty.
"Last November, at the board of governors, we had a resolution pass overwhelmingly. Of the 35 nations, only three voted against it, and that has never happened before," Davies noted.
Asked if the option for military action against Iran has receded for now, Davies said, "Nobody wants to see any solution other than a peaceful solution."