The Iranian army launched a large- scale military exercise on Saturday, the official IRNA news agency reported.
The first stage of the military exercise started in the northeastern, northwestern, western and southern parts of Iran, according to the report.
Assault and transport helicopters, parachutists, electronic war units and special forces will take part in the initial maneuver, said the report.
Meanwhile, the state-run television reported that the massive military exercise, aimed at introducing new defensive doctrine, would take place in 14 of Iran's 30 provinces and would last for about five weeks.
"Our main objective of this exercise is to adopt new tactics and use new equipment able to cope with possible threats," Brigadier General Kiumars Heydari, spokesman of the exercise, was quoted by the television as saying.
"We have been vigilant to what has happened in the world, and we have invested in both modern tactics and equipment," he added.
In addition, the television reported that a new anti-aircraft system was tested, which was able to "make the air space unsafe for the enemies" with cooperation of land forces, helicopters and fighter jets.
The army headquarters in the southeastern province of Sistan Baluchestan is commanding the ongoing war games, the television added.
Earlier reports said that 12 infantry regiments would participate in the exercise dubbed "The Blow of Zolfaghar". Zolfaghar is the sword used by Imam Ali, one of the most revered figures for Shiite Muslims.
In April, Iran launched another large-scale military exercise, the biggest in several years.
During the game, Iran said that it had tested advanced weapons including missiles and torpedoes.
The new military exercise came when Tehran is facing heightened pressure as a UN Security Council resolution urges it to halt uranium enrichment by Aug. 31.