In a morbid show of bravado, Iran has dug mass graves for US troops should the United States decide to implement Adm. Mike Mullen's contingency plan to strike Iran, a former commander of the Revolutionary Guard said. Adm. Mullen, the chairman of the US Joint Chiefs of Staff, said last week that the US military has a contingency plan to attack Iran, although he thinks a military strike is probably a bad idea.RELATED:'Strike may halt Iran's nuke program'Ahmadinejad: Obama made a big mistakeGen. Hossein Kan'ani Moghadam, who was the Guard's deputy commander during the 1980s, said graves have been dug in Iran's southwestern Khuzestan province, where Iran buried Iraqi soldiers killed during the ruinous 1980-88 war between the Islamic republic and Iraqi leader Saddam Hussein's regime."The mass graves that used to be for burying Saddam's soldiers have now been prepared again for US soldiers, and this is the reason for digging this big number of graves," Moghadam told The Associated Press Television News late Monday. He did not say how many were prepared.Footage obtained by APTN showed a large number of empty, freshly dug graves in a desert region of Khuzestan. The digging of the graves was first reported earlier this week by Iran's semi-official news agency Fars.Moghadam repeated warnings that Iran will retaliate against US bases in the Gulf if there is an attack on Iran. The US Navy's 5th Fleet headquarters is based just across the Gulf from Iran in Bahrain. If US forces attack, "Iran will have no choice but to strike the American bases in the region," he said. "The heavy costs of such a war will not be just on the Islamic Republic of Iran. America and other countries should accept that this would be the start of an extensive war in the region."The war of words has intensified between Iran and the United States after the UN Security Council imposed a fourth round of tougher sanctions in June in response to Iran's refusal to halt uranium enrichment, a technology that can be used to produce nuclear fuel or material for an atomic bomb.The US and Israel have said military force could be used if diplomacy fails to stop what they suspect is an Iranian nuclear weapons program.