Iran's military is going ahead with four days of war games despite rising criticism about the country's nuclear program.

State-run media said the military exercises began in eastern Iran either Friday or Saturday in an 800,000 square kilometer area near the border with Afghanistan.

The official Press TV said the initial phase of the drills was meant to test the ability of military units to react and deploy in case of an attack.

Both Israel and the United States have refused to rule out the use of military force to prevent Iran from building nuclear weapons. Israeli officials have also been hinting Israel may take action soon if Western sanctions fail to dissuade Tehran from developing nuclear weapons.

Iran has consistently denied allegations its nuclear program is being used for anything other than peaceful purposes.