TEHRAN, Iran (AP) – Iran has resumed small-scale enrichment of uranium, a senior Iranian nuclear negotiator said Tuesday, showing the country was determined to proceed with its atomic development despite international moves to restrict it.

The deputy secretary of the Supreme National Council, Javad Vaeidi, also told reporters that Iran would resume negotiations with Moscow next week over its plan to enrich Iranium uranium on Russian soil, a proposal designed to allay fears about Iran using enrichment to build nuclear weapons.

Iran had said Monday that negotiations with Russia, due to resume Thursday, had been indefinitely postponed. “The talks with Russia remain valid,” Vaeidi said, adding that an Iranian delegation would go to Moscow. “The final date of this visit will be Feb. 20.”

However in Moscow, Russian Foreign Ministry spokesman Mikhail Kamynin said his government was considering whether this date was suitable, the RIA-Novosti news agency reported Tuesday.

Vaeidi gave no indication whether Iran was looking more favorably at the plan now that international pressure over its nuclear program was increasing. Previously Iran said the plan is not satisfactory but is worth further negotiations.

Vaeidi told a press conference that enrichment of uranium resumed last week at Iran’s main enrichment plant in Natanz.

Asked if Iran had resumed large-scale enrichment, as required for producing fuel for nuclear reactors, Vaeidi replied: “No.”

“We need time to have 60,000 centrifuges,” he said, referring to the devices used in the enrichment process. Diplomats in Vienna, Austria, the site of the U.N. nuclear agency, had said Monday that Iran had started small-scale enrichment of uranium, a process that can produce fuel for an electricity-generating reactor or, in higher concentrations, material for an atomic bomb.

The world has long sought to stop Iran from enriching uranium, fearing that the process would bring it to the threshhold of possessing nuclear bombs. On Feb. 4, the International Atomic Energy Agency reported Iran to the U.N. Security Council and called on its government to suspend all enrichment-related activities.

Instead, the Iranian government suspended certain aspects of its co-operation with the IAEA and said it would steam full ahead with enrichment.

The United States had criticized Iran for restarting enrichment on Monday when White House press secretary Scott McClellan said: “They’re continuing to choose defiance and confrontation over cooperation and diplomacy.”

Vaeidi took pains to indicate that Iran was still open to negotiation.

“We are still prepared to find a formula to clarify the ambiguity in talks with our partners. At the same time, we will pursue our rights,” he said, referring to Iran’s insistence that it has the right to enrich uranium.

“The Iranian nation is united on one thing. Iranians don’t tolerate humiliation and threats,” Vaeidi said in an apparent reference to the country’s being taken to the Security Council, which could impose sanctions on Iran.

Moscow had proposed that Iran ship its uranium to Russia, where it would be enriched to a level suitable for nuclear reactors. It would then be returned to Iran for use at the Russian-built Bushehr plant, which is due to begin operating this year.

Germany expressed disappointment Monday after it was announced that the Iranian-Russian talks had been postponed. Germany, Britain and France, who have been negotiating with Iran without success, had seen the Russian plan as a solution to the dispute over Iranian enrichment.

China too expressed concern about the postponement. “China hopes that the talks between Russia and Iran can be held on schedule and achieve positive results,” Foreign Ministry spokesman Liu Jianchao said Tuesday, before Vaeidi said the talks would resume Monday.

Iran maintains its nuclear program is designed solely to generate electricity, but the United States and Israel claim the program is a cover for producing an atomic bomb.

Iran insists that as a signatory to the Nuclear Nonproliferation Treaty, which provides for peaceful nuclear development, it is entitled to enrich uranium for nuclear reactors. It has threatened to withdraw from the treaty if it was not allowed to exercise that right.

The world powers do not trust that Iran would confine enrichment to what is required for reactors because of its history of concealing aspects of its nuclear program. When the IAEA referred Iran to the Security Council, it accused the country of breaching the treaty.

The IAEA is to issue another report on Iran to the March meeting of its 35-nation board of governors. After that, the Security Council is expected to consider taking steps against the country.