Iran says it plans to sign an agreement Thursday allowing short-notice inspections of its nuclear facilities.
Iran's Vice President Gholamreza Aghazadeh made the announcement in Tehran Wednesday. Mr. Aghazadeh is also head of Iran's atomic energy agency.
Iran has come under heavy international pressure to sign the additional protocol to the Nuclear Non-Proliferation Treaty.
Western countries advised Iran that the step was needed to dispel U.S. led concerns that Tehran was trying to develop nuclear weapons.
Iran's government gave the formal go-ahead for the signing last week. But the agreement could still face opposition from Iran's Guardian Council, which must approve it. The council is dominated by conservative clerics, several of whom have spoken out against the agreement in the past.
Iran insists its nuclear program is peaceful and intended only for producing electricity. But in October, it admitted to the International Atomic Energy Agency that it had hidden certain activities from U.N. nuclear inspectors for 18 years.
Iran has already signed the basic Nuclear Non-Proliferation Treaty. But that treaty allows experts from the U.N. nuclear agency to carry out inspections only when after receiving permission ahead of time.