Tehran, Iran ? Iran tested a new anti-ship missile fired by a submarine during war games Sunday, raising worries it could disrupt vital oil tanker traffic in the Persian Gulf amid its standoff with the West about its suspect nuclear activities.

Iranian President Mahmoud Ahmadinejad took a tough tone on the nuclear issue, saying his country’s decision to pursue nuclear technology was irreversible.

His comments and the missile test came only days before a Thursday deadline imposed by the United Nations for Tehran to suspend the enrichment of uranium, a process the United States says the Iranians intend to use to build nuclear weapons. Enrichment can produce both reactor fuel and material for a warhead.

The Thaqeb, Farsi for Saturn, is Iran’s first missile that is fired from underwater and flies above the surface to hit its target, distinguishing it from a torpedo. A brief video showed the missile exiting the water and hitting a target less than a mile away.

While the missile showed some technological advances by Iran, its main importance seemed to be that it gives the country another means for targeting ships, along with the arsenal of torpedoes and other anti-ship missiles it already has.

Iran, which says its nuclear program is only aimed at generating electricity, has refused any immediate suspension and called the deadline illegal, though it says it is open to negotiations.

Ahmadinejad insisted Iran’s nuclear program was peaceful and said he saw no reason to give it up. “The great decision of the Iranian nation for progress and acquiring technology is a definite decision. There is no way back from this path,” he said in a televised speech after giving awards to 14 nuclear officials and scientists.

He said the United States should give up nuclear technology because it could not be trusted with it, having developed and used nuclear weapons.

The test-firing of the new missile underlines a card Iran can play in the nuclear standoff with the West – the ability to disrupt oil tanker shipments in the Gulf, through which about two-fifths of the world’s oil supplies pass.

Iran has given mixed signals about how it would retaliate if the confrontation with the United States escalates. The oil minister and other government officials have said Iran would never attack Gulf tankers, but the interior minister warned in March that all options for retaliation are open and noted Iran’s strategic position in the Gulf.

The test took place during large-scale military exercises that Iran has been holding since Aug. 19.