TEHRAN, Iran - Iran said Tuesday it was ready for "serious negotiations" on its nuclear program, offering a new formula to resolve a crisis with the West. A semiofficial news agency said the government was unwilling to abandon uranium enrichment - the key US demand.

Iranian technicians are seen at the Isfahan Uranium Conversion Facilities (UCF), 420 kms south of Tehran, in 2005. Iran called for talks as it delivered its response to a deal aimed at ending a long-running nuclear standoff but it did not say whether it had met the demands of the international community. [AFP\File]

Iran delivered its written response to a package of incentives offered by the United States and five other world powers to persuade Iran to roll back on its nuclear program and punishments if it does not. The world powers, the five permanent U.N. Security Council members plus Germany, have given Iran until Aug. 31 to accept the package.

The U.S. ambassador to the United Nations, John Bolton, said Washington will "study the Iranian response carefully" but was prepared to move forward with sanctions against Tehran if it was not positive. The White House held off commenting until it had studied the text. The European Union's foreign policy chief, Javier Solana, said the document was "extensive" and required "a detailed and careful analysis."

Iranian officials offered no details of the response, but it appeared geared at enticing those countries into further negotiations by offering a broad set of proposals vague enough to hold out hope of progress in resolving the standoff.

If the Iranians leave the door open to halting enrichment as talks progress, that would drive a wedge in the Security Council between the Americans, British and French on one side and the Russians and Chinese on the other. Last month, Russia said the Council was in no rush to pressure Iran, striking a more conciliatory tone than the United States.

Tuesday's announcement was the latest development in the yearlong standoff over Tehran's nuclear program. Iran says it wants to master the technology to generate nuclear power. But critics say Iran is interested in uranium enrichment because it can also be used to make the fissile core of nuclear weapons.

The current drama is playing out in the wake of fears that the ability of the pro-Iranian Hezbollah guerrillas in Lebanon to withstand 34 days of Israeli bombardment has emboldened hard-liners in Tehran to risk a showdown with the Americans, who are bogged down in neighboring Iraq. There has also been speculation in the West that Iran encouraged Hezbollah to provoke the Israelis to distract attention from its nuclear ambitions.

Iran has pursued a confrontational stance on the nuclear issue since the election of President Mahmoud Ahmadinejad last year. The hard-line president has used the nuclear issue to encourage a sense of national pride among Iranians by standing up to the United States and other Western countries.

On Tuesday, Iran's top nuclear negotiator, Ali Larijani, hand-delivered his government's response to ambassadors of Britain, China, Russia, France, Germany and Switzerland, which represents U.S. interests - nine days before a Security Council deadline for Iran to halt uranium enrichment or face economic and political sanctions.

Larijani refused to disclose whether the response included an offer to suspend uranium enrichment. But the semiofficial Fars news agency reported that Iran rejected calls to suspend "nuclear activities" or uranium enrichment and "instead has offered a new formula to resolve the issues through dialogue."

The state-run television quoted Larijani as telling the diplomats Iran "is prepared as of Aug. 23rd (Wednesday) to enter serious negotiations" with the countries that proposed the incentives package.

The Irna official news agency reported that "Larijani said Iran's answer has logically, fairly and constructively addressed demands of the proposed package, recommending the P5+1 group to return to the negotiation table immediately despite the false atmosphere created against Iran that it was buying time."

Last month, the Security Council set an Aug. 31 deadline for Iran to halt uranium enrichment or face economic and political sanctions. Iran called the resolution "illegal" but had said it was willing to offer a "multifaceted response" to an incentives package that the six powers offered in June.

Iranian officials familiar with Larijani's response said Tehran offered a "new formula" to resolve the dispute. The officials spoke on condition of anonymity because of the sensitivity of the information.

"Iran has provided a comprehensive response to everything said in the Western package. In addition, Iran, in its formal response, has asked some questions to be answered," one official said without providing more details.

But the Iranians have been signaling they are not prepared to abandon uranium enrichment as a precondition to talks. Last month, a senior Iranian lawmaker said the country's parliament was preparing to debate withdrawal from the Nuclear Nonproliferation Treaty if the U.N. Security Council adopts a resolution to force Tehran to suspend enrichment.

On Monday, Iran's supreme leader, Ayatollah Ali Khamenei, said the Islamic Republic "has made its own decision and in the nuclear case, God willing, with patience and power, will continue its path." Khamenei accused the United States of putting pressure on Iran despite Tehran's assertions that its nuclear program was peaceful.

Iran's former foreign minister Ali Akbar Velayati, who is now a top adviser to Khamenei, said Iran's national interests, not the West's demands, should be the basis for Iran's decision.

"What we have achieved in nuclear technology is worth more than the pressures against us at the international stage," the semiofficial Iranian Students News Agency quoted Velayati as saying Tuesday.

In February, Iran for the first time produced its first batch of low-enriched uranium, using a cascade of 164 centrifuges.

In the last few weeks, Iran prevented U.N. nuclear agency inspectors from inspecting an underground site meant to shelter its uranium enrichment program from attack, diplomats said Monday.

The head of the International Atomic Energy Agency, Mohamed ElBaradei, is to report by Sept. 11 to the agency's board on Iran's compliance with the U.N. deadline to freeze enrichment and other aspects of Tehran's cooperation with U.N. inspectors.

The Western incentives package has not been made public but some details have leaked. They include an offer to lift a ban on sales of Boeing passenger aircraft, providing Iran with some nuclear technology to build reactors for civilian purposes and guaranteeing a supply of nuclear fuel.