Iran said Sunday it was seriously considering incentives to halt its nuclear program and asked the United States and other countries to be patient while Teheran weighs its response.
But Iran's oil minister warned again that his petroleum-rich country could disrupt the world's oil supply if the standoff leads to open conflict.
"If the country's interests are attacked, we will use oil as a weapon," state television quoted Kazem Vaziri Hamaneh as saying.
That would drive oil prices above $100 US a barrel, he said.
Foreign Ministry spokesman Hamid Reza Asefi told reporters that specialized committees in key state agencies were studying the nuclear incentives offered June 6 by the United States, Britain, China, France, Russia and Germany.
"The package contains legal, political and economic dimensions. All its dimensions have to be studied," Asefi said. "We recommend to Europeans that accuracy should not be sacrificed for the sake of speed."
Asefi said the package required careful study before Tehran delivered its formal response.
"The reason that there can't be a speedy response is that we have to hold serious discussions on the contents," he said. "We are taking it seriously."
President Mahmoud Ahmadinejad has said Iran would take until mid-August to respond to the incentives package, prompting President Bush to accuse Tehran of dragging its feet.
Although details have not been made public, diplomats familiar with its contents have said the offer includes economic incentives and a provision for the United States to offer Iran some nuclear technology, lift some sanctions and join direct negotiations.
The proposal calls for Iran to suspend uranium enrichment - which can produce peaceful reactor fuel or fissile bomb material - during negotiations.
It calls for a long-term moratorium on enrichment until the international community is convinced that Tehran's nuclear aims are peaceful. Iran says it only wants to generate nuclear energy.
Iran has said it will not give up enrichment but indicated it may temporarily suspend large-scale activities to ease tensions.
Asefi said dialogue was the only way to deal with Iran's nuclear program, but he rejected the precondition that Iran halt uranium enrichment before talks start.
Iran's top nuclear negotiator, Ali Larijani, suggested Turkey could be a "good bridge" to resolve differences between Iran and the West.
Larijani suggested Turkey play a mediating role after meeting with Turkish Foreign Minister Abdullah Gul on Sunday.
"Deliberations with friends helps this path, especially friends that are close to both parties," the official Islamic Republic News Agency quoted Larijani as saying. "These negotiations and deliberations can be a good bridge to resolve this."
Gul's trip to Iran came ahead of a visit to the US early next month.
Germany and Iran's foreign ministers said Saturday that they agreed that Iran would meet again with European Union foreign policy chief Javier Solana to go over the incentive offer. German Foreign Minister Frank-Walter Steinmeier said he expected the first meeting "in the next week."
Iran is the world's fourth-largest oil exporter and the second-largest producer in the Organization of Petroleum Exporting Countries. The Islamic republic exports about 2.5 million barrels a day.
The oil minister's sharp comments marked the second time in a month that Iran threatened to disrupt the world's oil supply if Tehran is punished over its nuclear program.
Iran's supreme leader, Ayatollah Ali Khamenei, also has said the United States and its allies would be unable to secure oil shipments passing out of the Persian Gulf through the strategic Strait of Hormuz to the world markets.