The United States, in a major policy shift toward Iran, said today it would join European governments in talks with Tehran if it suspended its nuclear enrichment program.
President George W Bush said the United States was taking a "leadership position" to resolve the Iran nuclear dispute diplomatically, but Secretary of State Condoleezza Rice stressed the military option was still on the table.
"It's time to know whether Iran is serious about negotiation or not," Ms Rice told a news conference.
Ms Rice said the talks offer was part of a package of incentives and sanctions whose "essential elements" have been agreed with Britain, France and Germany and will be discussed further on Thursday when ministers meet in Vienna.
The Iran government had no immediate comment on the US offer, but the foreign policy spokesman for its parliament reportedly said the US precondition was "not suitable".
"The fact that the US has announced its readiness for talks can be viewed as positive but the US precondition is not suitable," Kazem Jalali, spokesman for parliament's foreign policy and national security committee, said in comments carried by Iran's student news agency ISNA.
"The Islamic Republic of Iran has announced that it does not have halting enrichment on its agenda.
Washington's European allies France, Britain and Germany welcomed the US proposal and said they hoped it would push along negotiations.
"We can only hope that those in charge in Tehran understand the scope of this announcement and will react accordingly," German Foreign Minister Frank-Walter Steinmeier told a news conference with his Dutch counterpart.
Tehran has said it is willing to negotiate on the number of uranium-enriching centrifuges it uses for research, but has stressed it would not stop running the devices entirely as the UN Security Council has called for.
Nasser Hadian, an Iranian political analyst in Tehran, said Iran was unlikely to agree to suspending all its enrichment activities but might agree to limitations.
"Some Iranian politicians will reject it (the offer) immediately, but (Iran's chief nuclear negotiator Ali) Larijani will have a more positive nuance saying we welcome the negotiations but we will not halt the enrichment activities," said Hadian.