Amid growing concerns of renewed conflict in the Middle East, the Tehran regime has shaken up the leadership of the Islamic Revolutionary Guard Corps, putting a veteran general who operated in Lebanon with Hezbollah in command of its ground forces.

Meantime, in an indication that the Americans are also making preparatory moves, the Pentagon is reported to be shipping hundreds of "bunker-buster" deep-penetration bombs to the Indian Ocean island of Diego Garcia.

The British-owned island, about 1,000 miles south of India, was used by U.S. forces to launch airstrikes against Iraq during the 1991 and 2003 wars in the Gulf.

The Sunday Herald of Scotland reports that in January the Pentagon contracted Superior Maritime Services of Florida to ship a cargo of munitions that includes 195 1,000-pound BLU-110 and 192 2,000-pound BLU-117 "bunker busters" to Diego Garcia.

This raised speculation that the ordnance was being deployed for possible air attacks on Iran's key nuclear facilities, most of which are deep underground, and other strategic targets.

U.S. B-2 stealth bombers are based on Diego Garcia. Although it is part of the British Indian Ocean Territory, the Americans use it as a military base under a 1971 agreement.

In Tehran, Sunday's appointment of Brig. Gen. Mohammad Pakpour by Iran's supreme leader, Ayatollah Ali Khamenei, indicated the regime plans to wage an asymmetrical war if the United States attacks Iran's nuclear infrastructure.

Pakpour will serve under Maj. Gen. Mohammad Ali Jaafari, the IRGC commander. Jaafari is a respected strategist who, before he was appointed by Khamenei in 2007, was director of a Tehran think tank that concentrates on asymmetric defensive strategy.

"The combination of the two personalities reflects Iran's true defensive strategy," the U.S. global security consultancy Stratfor said.

Khamenei's decree appointing Pakpour noted, "It is expected that you will maintain the devoted personnel, use innovative methods and modern technology and draw up the necessary plans to carry out your responsibilities and boost the level of preparedness."

His experience with Hezbollah, the only Arab force to make a strong showing against the Israelis, should prove invaluable.

The Shiite movement, heavily armed by Iran and Syria and which functions more like a conventional army than a guerrilla force, will be a key instrument of Iranian retaliation in the event that hostilities break out.

If Israel is involved, Hezbollah can be expected to mount a major offensive involving thousands of rockets and missiles as well as seasoned ground forces who fought the Israeli army to a standstill in their monthlong 2006 war.

Military analysts say that if Iran goes to war with the United States, Tehran expects its heavily outgunned and outnumbered air force, with few advanced combat aircraft, and probably its naval forces as well, will be severely mauled, if not decimated by U.S. firepower.

In that scenario, the 125,000-strong IRGC, the most powerful fighting force in the Iranian military, would deploy its infantry and commando units to wage a guerrilla-style war against U.S. ground forces.

It is highly unlikely that the Americans would risk actually invading Iran, with its vast deserts and mountains, because it would take huge land forces to do so and the United States is already heavily engaged in the Afghanistan-Pakistan theater.

"In addition to reprisal attacks by Hezbollah and attempts to mine the Strait of Hormuz, truly defending Iran against actual invasion -- something no one but the Iranians are contemplating -- would look a lot like southern Lebanon in 2006, with irregular, asymmetric forces using Iran's rugged terrain to wear down any invader," Stratfor said in an analysis.

Also Sunday, Iranian President Mahmoud Ahmadinejad, himself a former IRGC commander who conducted behind-the-lines operations during the 1980-88 war with Iraq, named a high-powered team tasked with minimizing the effect of war damage on the country in the event of war.

The committee is headed by Maj. Gen. Hassan Firouzabadi, chief of staff of Iran's armed forces and includes the ministers of defense, interior and science.

"Both moves reflect relatively long-standing Iranian thinking and are prudent military planning but nevertheless are emblematic of a continually defiant Iran remaining wary that a potential miscalculation in its careful management of the nuclear crisis could lead to an attack," Stratfor concluded.