Top diplomats from six major powers are deeply disappointed with Iran's refusal to suspend uranium enrichment and will discuss possible U.N. sanctions to force it to act, British Foreign Secretary Margaret Beckett said after a high-level meeting Friday.

Tehran had two choices when the United Nations demanded that it suspend enrichment, and "we regret that Iran has not yet taken the positive one," Beckett said.

Diplomats from the United States, Britain, France, Germany, Russia and China had gathered in London for the meeting to decide a next step in the nuclear standoff with the defiant country.

A statement Beckett read stopped short of declaring that negotiations with Iran by European Union foreign policy chief Javier Solana's had failed, but said the diplomats were "deeply disappointed that he has had to report that Iran is not prepared to suspend its enrichment-related reprocessing activities."

The meeting was delayed by U.S. Secretary of State Condoleezza Rice's plane, which suffered technical problems in Iraq. A helicopter eventually took her to the meeting, which was already under way.

Ahead of the talks, Russian Foreign Minister Sergey Lavrov said new measures against Iran are not out of the question, but a top Russian diplomat said Russia and China agree on the "unacceptability" of the use or threat of force against Iran in the dispute over its nuclear program.

"Iran is a large regional nation that has noticeable influence on the situation in a wide and very tense region. Speaking to it in the language of threats and ultimatums, attempts to drive it into a corner, are counterproductive," the agency quoted Deputy Foreign Minister Alexander Alexeyev as saying.

Even in the face of sanctions, though, Iran is not likely to stop its enrichment program. A source close the regime told FOX News Iran feels very emboldened and in a position of strength, because it thinks Hezbollah won the war against Israel. Another source says that if faced with sanctions, it will back down.

CountryWatch: Iran

To avoid alienating the Russians and the Chinese — both major commercial partners of Iran — any sanctions are likely to be relatively mild. Possibilities include embargoes on missile and nuclear technology and travel bans and other penalties on Iranian officials involved in the country's nuclear program.

Iranian President Mahmoud Ahmadinejad said Thursday that his country would not be intimidated.

Click here to go to FOXNews.com's Iran Center.

"Those who threaten Iran by sanctions and embargo should know that this nation lived under the hardest situation in the past 27 years and achieved nuclear technology. This nation will not be frightened by the threats," state-run television quoted Ahmadinejad as saying.

Talks between European and Iranian negotiators have failed to persuade Tehran to suspend its enrichment program.

Iran insists its enrichment of uranium is purely for the peaceful purpose of nuclear energy. But the United States and many European nations believe Iran wants to enrich uranium to produce nuclear weapons.

The six nations remain divided over how tough to get with Tehran.

Russia's foreign minister said it was too soon for sanctions, while the U.S., Britain and France think it's time to move ahead with limited measures.

Britain announced the planned talks after hours of conflicting reports about whether the ministers would meet, suggesting jostling among diplomats behind the scenes.

Britain's U.N. Ambassador Emyr Jones Parry said Thursday he expected Iran's file to return to the Security Council "in the course of next week." He said council members would discuss the possibility of adopting "measures under Article 41 against Iran."

Article 41 authorizes the Security Council to impose sanctions that do not involve the use of armed forces, such as economic penalties, breaking diplomatic relations or banning air travel.

The council gave Iran until Aug. 31 to suspend enrichment in return for a package of incentives or face punishments under Article 41, but the council has held off any action because of talks between the EU and Iran's top negotiator Ali Larijani.

Solana conceded Wednesday that "endless hours" of talks with Larijani had made little progress and suggested the dispute could wind up at the U.N. soon. But he stressed Thursday that dialogue with Iran must continue even if nuclear talks fail.

"We shall not spare any effort to try to move forward when it is possible," he said in Rome. "It is not possible at the moment, but that doesn't mean it will not be possible later."

FOX News' Amy Kellogg and the Associated Press contributed to this report.