"There will be meetings Wednesday in Vienna," one diplomat said Tuesday.

Other diplomats confirmed the meeting would take place at the International Atomic Energy Agency (IAEA) but did not say at what level.

The first diplomat said Iran's vice president and atomic energy chief, Gholam Reza Aghazadeh, would head the delegation and would meet with IAEA director general Mohamed ElBaradei.

The UN Security Council has set a non-binding deadline for Iran to freeze ultra-sensitive uranium enrichment, the process that makes fuel for nuclear power reactors but can also be used to make the raw material for atom bombs.

If Iran does not heed the Friday deadline, the Security Council could make it legally binding for Tehran to suspend enrichment and cooperated with an IAEA inspection of the country's nuclear program.

This could open the door to international economic sanctions or even military action.