Iran has threatened to take action if the US Navy moves an aircraft carrier into the Persian Gulf.
Army chief Ataollah Salehi said the US had moved an aircraft carrier out of the Gulf because of Iran's recent naval exercises, and Iran would take action if the ship returned.
"Iran will not repeat its warning...the enemy's carrier has been moved to the Sea of Oman because of our drill. I recommend and emphasise to the American carrier not to return to the Persian Gulf," army chief Salehi said.
"I advise, recommend and warn them over the return of this carrier to the Persian Gulf because we are not in the habit of warning more than once."
However the Pentagon says it will keep sending US aircraft carriers into the region, despite the threat.
"The deployment of U.S. military assets in the Persian Gulf region will continue as it has for decades," Pentagon spokesman George Little said in a statement.
The aircraft carrier USS John C Stennis leads a US Navy task force in the region. It is now in the Arabian Sea providing air support for the war in Afghanistan, according to a spokeswoman for the US 5th Fleet.
The carrier left the Gulf on 27 December on a "preplanned, routine transit" through the Straight of Hormuz, she said.
Over 40% of the world's traded oil flows through that narrow straight - which Iran threatened last month to shut if sanctions halted its oil exports.
The statement from iran comes as new US and EU financial sanctions take a toll on the Iranian economy.
The prospect of sanctions targeting the oil sector in a serious way for the first time has hit Iran's rial currency, which reached a record low today and has fallen by 40% against the dollar in the past month.
