TEHRAN, (Reuters) – Iran responded on Friday to an incentives package offered by six world powers aimed at resolving a standoff over the Islamic Republic’s disputed nuclear ambitions, the official IRNA news agency said.

The agency quoted a senior source at Iran’s Supreme National Security Council as saying Tehran’s reply was submitted to European Union foreign policy chief Javier Solana, but did not give any details about its content.

There was no immediate confirmation from Solana’s office in Brussels that Iran’s response had been delivered.

The offer of economic and other incentives proposed by the United States, China, Russia, Germany, Britain and France was presented to Iran by Solana last month to try to persuade it to halt work they fear is aimed at making nuclear bombs.

Iran has said it is willing to enter talks about the package but has repeatedly rejected demands to halt uranium enrichment, which can have both civilian and military uses.

The dispute over its nuclear programme has sparked fears of a military confrontation and contributed to oil prices rising to record highs on global markets.

“The Islamic Republic of Iran’s response to Solana and the (six powers’) foreign ministers was submitted to Solana by Iran’s ambassador to Brussels,” the source told IRNA, adding it was signed by Foreign Minister Manouchehr Mottaki.

State radio earlier said Saeed Jalili, Iran’s chief nuclear negotiator, talked to Solana by telephone and that the two agreed to hold more talks later this month.

Jalili said Iran, which has earlier presented its own package of proposals aimed at resolving the row, had prepared its response by concentrating on common ground between the two sides and with a “constructive and creative outlook.”

The incentives package says formal negotiations on the offer can start as soon as Iran suspends uranium enrichment.

It is a revised version of an offer spurned by Iran in 2006, which included civilian nuclear cooperation as well as wider trade in aircraft, energy, high technology and agriculture.

Analysts and diplomats say they detect a softer tone from Iran towards the nuclear incentives offer, but that this may be a bid to buy time rather than a shift to accept world powers’ key demand of a halt to uranium enrichment.

They say it is also uncertain whether Iran might accept a “freeze-for-freeze” idea to get preparatory talks going.

Such a step would involve Tehran freezing expansion of nuclear enrichment in return for world powers halting moves to add to three rounds of U.N. sanctions already imposed.

Enriched uranium can be used as fuel for power plants but also, if refined much more, provide material for nuclear bombs.

Iran, the world’s fourth-largest oil exporter, says its nuclear programme is solely aimed at generating electricity so that it can sell more of its oil and gas.

An Iranian official, speaking on condition of anonymity to Reuters last month, said time was on Iran’s side. “We will review the package but not the part about enrichment freeze … We are moving forward with our work and Iran’s nuclear capability is being constantly augmented,” said the official, who was involved in talks with Solana in Tehran.