U.N. Security Council (file photo)

The five permanent United Nations Security Council members and Germany have failed to agree on a strategy for pressuring Iran to halt its controversial nuclear program. Approval of a hoped-for common position statement has been delayed to allow more time for diplomacy.

Russia and China at least temporary blocked a U.N. Security Council statement that would urge Iran to stop enriching uranium for possible use in nuclear weapons. The United States, along European allies Britain, France and Germany, had hoped the statement would be adopted Tuesday.

Iran insists its nuclear program is for peaceful purposes. However, the United States and several of its European allies think otherwise.

But those hopes were dashed when a Monday meeting of senior diplomats of the six nations outside U.N. headquarters failed to settle on common language. One diplomat, who requested anonymity, called the negotiations "difficult."

U.S. Undersecretary of State Nicholas Burns emerged from the talks expressing optimism that agreement would eventually be reached. But, in an apparent reference to the Chinese and Russian objections, he suggested that the four-and-a-half hour session had achieved little.

"It is clear from today's meeting that there will have to be more meetings in New York," he said. "There's certainly going to be further contact among capitals, but we remain convinced that we will achieve a presidential statement. It may take a little bit of time."

Burns said the United States remains committed to diplomacy on Iran. He emphasized that there is unity among all six parties to the talks on the basic approach for pressuring Tehran to comply with the demands of the International Atomic Energy Agency.

"All of us agreed Iran is out of compliance with its international commitments," he said. "All of us agreed Iran is traveling down the road towards enrichment and reprocessing that will be fundamentally detrimental to interests of the world of non-proliferation and peace and security. And, all of us agreed we should stay united and stay together to send one message to the Iranians and convince the Iranians to roll back their nuclear program."

China's Ambassador Wang Guangya would only say discussions are continuing. But, in recent days, he has said Beijing wants a slower pace of diplomacy and assurances that the IAEA will keep the lead role in ensuring Iranian compliance with its international obligations.

News reports from IAEA headquarters in Vienna say Britain is already looking ahead to possible steps in the event Iran fails to comply with the atomic agency's call for an end to its nuclear program.

The host of Monday's talks in New York, British Foreign Office Political Director John Sawers says Tehran must accept the IAEA directives, to assure the world it is not building nuclear weapons.

"It's essential that Iran take the steps in order to start the process of rebuilding confidence in its nuclear intentions," he said. "Those steps that Iran needs to take were set out in the IAEA board resolution on fourth February. We deeply regret Iran has not yet come into line with those requirements and indeed has ceased cooperation."

Monday's meeting came hours after Iranian President Mahmoud Ahmedinejad vowed that his country would not give in to international pressure to give up its nuclear program. In a televised speech marking the Iranian New Year, he said the Islamic republic had attained nuclear technology on its own, and no one could take it away.