UNITED NATIONS – As Foreign Ministry officials from the leading Security Council main powers failed to agree in New York yesterday on a unified diplomacy on Iran’s nuclear program, Tehran stepped up its quest for atomic weapons.

Reports on a new round of diplomacy stemming from a British initiative for negotiations with Tehran were denied yesterday. And far from advancing the unity among members of the Security Council, yesterday’s high-level meeting at the British mission to the United Nations might be a “step backward,” as one Western diplomat described it.

According to reports from Vienna, meanwhile, Iran was on the verge of running a cascade of 164 centrifuges of uranium hexafluoride gas, known as UF-6. Earlier this year, putting UF-6 into one centrifuge at Iran’s Nantanz facility was considered a step toward enrichment at levels needed for weapons. Iran later was able to string cascades of 10, and then 20 centrifuges.

“Iran is on the verge of operating a 164-centrifuge cascade with UF6,” an unnamed Western diplomat at the Vienna-based International Atomic Energy Agency told AFP yesterday. Once they learn the technique, Iranian nuclear scientists will be able to cascade thousands of centrifuges, nuclear experts agree.

“Once you learn how to make one washing machine, you can make a thousand washing machines,” a senior American official told reporters recently, describing advances in Iran’s weapons program.

Acknowledging Iran’s pace toward weapon capabilities, top diplomats flown here from capitals of the five permanent members of the Security Council nevertheless failed to reach an agreement on how diplomacy should proceed.

“All of us agree that Iran is now traveling down the road towards enrichment and reprocessing that is fundamentally detrimental to the interest of the world of non-proliferation and peace and security,” said Undersecretary of State Nicholas Burns after the meeting.

But he acknowledged no agreement was reached on a unified Security Council statement. “It may take a little bit of time, but it’s going to be worth the time,” he said. “All of us agreed that we should stay united and stay together to send one message to the Iranians.”

Yesterday’s 4 1/2-hour meeting brought Mr. Burns together with foreign ministry directors from three European powers – France, Germany, and Britain – as well as their Russian and Chinese counterparts. Despite the high level, some diplomats said that now the main players were even less united than in the last few weeks, when U.N. ambassadors were negotiating a united council statement.

“The discussion was on how the Council must put its weight to reinforce the authority of the IAEA and on the level of precision of the message to be sent to Iran,” French U.N. ambassador, Jean Marc de-la Sabliere said after the meeting. “France’s opinion is that this message must be strong and precise.”

“It’s a step backwards,” said another Western diplomat, who requested anonymity. The sticking point remained Russia’s refusal to get tough with the Iranians, he added.

Russia has opposed creating an IAEA reporting mechanism to the Security Council to record Iran’s failure to comply with the nonproliferation treaty and with the agency’s inspectors. Moscow insists that the main diplomatic efforts should be conducted at the IAEA in Vienna, and not at the Security Council, where sanctions could eventually be imposed.

“The IAEA is always going to have a responsibility to inspect Iran and to bring it into compliance,” Mr. Burns said. “But the issue has clearly moved also to the Security Council. It’s in both places. It’s not going to leave the Security Council.”