TEHRAN (AFP) - Iran’s military on Tuesday warned one of the US navy’s biggest aircraft carriers not to return to the Gulf, in an escalating showdown over Tehran’s nuclear drive that could pitch into armed confrontation.“We advise and insist that this warship not return to its former base in the Persian Gulf,” said Brigadier General Ataollah Salehi, Iran’s armed forces chief.“We don’t have the intention of repeating our warning, and we warn only once,” he was quoted as saying by the armed forces’ official website. The US carrier would face the “full force” of the Iranian navy if it returns, a navy spokesman, Commodore Mahmoud Mousavi, told Iran’s Arabic television service Al-Alam.The ominous message came just after Iran completed 10 days of naval manoeuvres at the entrance to the Gulf to show it could close the strategic oil shipping channel in the Strait of Hormuz if it felt threatened.In the climax of the war games on Monday, Iran test-fired three missiles - including a new cruise missile - designed to sink warships. The aircraft carrier Salehi was referring to is the USS John C Stennis, one of the US navy’s biggest warships. The massive, nuclear-powered vessel transports up to 90 fighter jets and helicopters and is usually escorted by around five destroyers. It is close to finishing its seven-month deployment at sea.The carrier last week passed through the Strait of Hormuz heading east across the Gulf of Oman and through the zone where the Iranian navy was holding its manoeuvres.The US Defence Department called its passage “routine”.It was not immediately known if the USS John C Stennis was scheduled to return to the Gulf, or if it was to be replaced by another of the United States’ 11 aircraft carriers.Iran’s armed forces chief-of-staff, General Hassan Firouzabadi, added to the defiance by saying Tuesday that the Revolutionary Guards, an elite military force apart from the regular defence services, would soon hold its own naval manoeuvres in the Gulf. Foreign ministry spokesman Ramin Mehmanparast told reporters that “the foreign forces” present in the Gulf - meaning the US Navy - “are against the security of the region.” He said Iran’s war games underlined his country’s commitment to ensuring “stability and security in the region.” The potential for an Iran-US conflict sent a shiver through oil markets Tuesday, pushing oil prices up around $2 a barrel.There was no sign of a let-up in the tensions. At the weekend, US President Barack Obama signed into law new sanctions targeting Iran’s central bank, which processes most of the Islamic republic’s oil export sales.The European Union, which is mulling an embargo on Iranian oil, is expected to announce further sanctions of its own at the end of January.French Foreign Minister Alain Juppe said he was convinced Iran was pursuing nuclear weapons, and he wanted to see “stricter sanctions” applied on Iran. The Western sanctions add to four sets of UN sanctions imposed over Iran’s nuclear activities.Despite the increasingly bellicose stand Iran’s military was taking, Tehran suggested it was keeping the door open to negotiating with world powers over its nuclear programme.