TEHRAN, Iran -- Iran offered Tuesday to resume nuclear talks with the United States and other world powers next week after pushing for a shift of venue to Turkey to give Tehran an ally on the sidelines.

It was not immediately clear, however, whether the mothballed negotiations could be restarted as quickly as next Monday -- under the Iranian proposal carried by the semiofficial Mehr news agency.

After the Iranian announcement, Turkish Prime Minister Recep Tayyip Erdogan said no firm date has been set for the talks, Turkey's state-run Anatolia news agency reported.

But the proposal attributed to Foreign Minister Manouchehr Mottaki shows Iran's apparent eagerness to reopen dialogue over its nuclear ambitions after facing tighter international economic sanctions.

It also displays the growing diplomatic aspirations of NATO-member Turkey as a bridge between the West and Islamic world. Turkey is a longtime Western ally, but its Islamic-oriented leadership has been gradually shifting its priorities toward boosting ties with Iran and other Muslim nations.

Talks with the six nations -- the United States, Russia, China, Britain, France and Germany -- collapsed last year after Iran balked at a U.N.-drafted plan to send most of its enriched uranium abroad in exchange for reactor-ready fuel for its lone power reactor and a separate facility to make isotopes for cancer treatment.

The six powers suspect Iran is seeking to develop a nuclear weapons capability under the cover of a civil energy program. Iran denies that, saying it only has peaceful aims, such as power generation.

Iran accepted a uranium-for-fuel swap proposal from allies Brazil and Turkey, but the six nations said that offer fell short of their demands to ensure that Iran does not possess the raw materials for a nuclear weapon.

The U.N. Security Council imposed a fourth round of tough sanctions against Iran in June over its refusal to halt enrichment.

Although Iran has opened the door to restart talks, it has not given any indication of backing off Western demands to halt enriching uranium -- which can be used to make fuel for power plants as well as material for warheads.

The Mehr agency quoted Mottaki as saying talks were "expected" to start Monday. Mottaki had earlier suggested Turkey as the venue.

Mottaki said both Iran and the West should show "flexibility" for setting date and place of the talks.

"Then it will not be hard to set them," he was quoted as saying.

He also urged the six nations to soften their stance toward Iran.

"In the past, we witnessed confrontation instead of a constructive" approach, he was quoted as saying.