FACTBOX-How big is Iran's military?

Nov 23 (Reuters) - Iran's armed forces launched five days of large-scale air defence military exercises on Sunday to show off the country's deterrence capabilities in the face of pressure from the West over its nuclear programme.

The display of military muscle comes at a time of rising tension between Iran and six major powers which fear Tehran's nuclear programme is aimed at producing nuclear weapons. Tehran denies this is the programme's purpose.

Following are some details about Iran's military capability. The totals include equipment held by the Revolutionary Guards, which operate on land, at sea and in the air:

* ARMED FORCES:

-- Iran has more than 523,000 personnel on active service. Major General Ataollah Salehi is the armed forces chief.

* ARMY:

-- The army comprises about 350,000 men, including 220,000 conscripts. The Islamic Revolutionary Guards Corps, viewed as the most loyal guardian of the ruling system, has another 125,000 men. In 2004 the army was organised in four corps, with four armoured divisions and six infantry divisions.

-- There are 1,600 tanks including some 100 Zulfiqar locally produced main battle tanks. A large number of Iran's tanks are elderly British-made Chieftains and U.S.-made M-60s.