A top Iranian military officer says Iran will conduct air defense war games aimed at protecting the country's nuclear facilities from attacks.

Brigadier-General Ahmad Mighani told Iran's Fars news agency the large-scale drills will begin Sunday and will last for five days. He said they will involve Iran's elite Revolutionary Guards and other military units.

Iranian media say the drills will cover an area of some 600,000 square kilometers in parts of central, western and southern Iran where the country's nuclear facilities are located.

Iran often holds military exercises to show its readiness to fight perceived threats to its controversial atomic program. The United States and Israel have not ruled out military action if diplomacy fails to resolve the Iranian nuclear issue.

On Friday, officials from six world powers expressed disappointment at Iran's refusal to accept a United Nations-brokered plan calling on Tehran to ship its uranium abroad for enrichment.

Representatives from the five permanent members of the U.N. Security Council (the United States, Britain, France, Russia and China) and Germany met Friday in Brussels to discuss the enrichment plan and other issues related to Iran's nuclear program.

Iran has said it will not process its enriched uranium abroad and will consider only a uranium-for-fuel swap inside Iran. The enrichment plan is aimed at alleviating international concerns that Iran is developing atomic weapons.

Enriched uranium produces fuel that can be used for civilian purposes or, in highly enriched form, for nuclear weapons. Iran says its nuclear program is for peaceful purposes.