Tehran, Iran ? Iran will begin large-scale air defense war games today aimed at protecting its nuclear facilities from possible attack, a senior military commander said Saturday, reflecting the country’s concern that Israel could make good on threats to strike militarily.

The drill comes as a top clerical official renewed his threat to target “the heart of Tel Aviv” should Israel attack Iran.

The five-day drill will involve Iran’s elite Revolutionary Guard and the regular army and will cover 230,000 square miles — or about 600,000 square kilometers — of central, western and southern Iran, said air force Gen. Ahmad Mighani.

As Iran has pressed forward with its nuclear program, Israel has repeatedly threatened military action to prevent Tehran from obtaining nuclear weapons. The U.S. also has not ruled out military action should diplomacy fail to resolve the dispute over Iran’s nuclear activities.

Washington and its European allies suspect Iran aims to use a civilian nuclear program as cover to produce weapons, and Iran has effectively rejected a new U.N. proposal aimed at easing those concerns. Tehran denies any intention to make nuclear weapons and says it only wants to generate power.

The defense drill will involve an attack by airplanes representing a hypothetical enemy.