TEHRAN, Iran - Iran conducted its second major test of a new missile within days on Sunday, firing a high-speed torpedo it said no submarine or warship can escape at a time of increased tensions with the U.S. over its nuclear program.

The tests came during war games that Iran's elite Revolutionary Guards have been holding in the Persian Gulf and the Arabian Sea since Friday.

Iranian President Mahmoud Ahmadinejad speaks during a rally of paramilitary forces in support of the country's nuclear program in Tehran, Iran, Saturday, Nov. 26, 2005. [AP]

On the maneuvers' first day, Iran said it successfully tested the Fajr-3 missile, which can avoid radar and hit several targets simultaneously using multiple warheads.

The new torpedo, called the "Hoot," or "whale," could raise concerns over Iran's power in the Gulf, a vital corridor for the world's oil supplies and where the U.S. Navy's 5th Fleet is based. During Iran's war with Iraq in the 1980s, Iranian ships attacked oil tankers in the Gulf, and Iran and the U.S. military engaged in limited clashes.

Iran's state television stopped its normal programs to break news of the torpedo test, showing it being launched from a ship into the Gulf waters, then hitting its target, a derelict ship.

Gen. Ali Fadavi, deputy head of the Revolutionary Guards' navy, said the ships that fire the Iranian-made Hoot had radar-evading technology and that the torpedo ¡ª moving at 223 miles per hour ¡ª was too fast to elude.

"It has a very powerful warhead designed to hit big submarines. Even if enemy warship sensors identify the missile, no warship can escape from this missile because of its high speed," Fadavi told state television.

The Hoot's speed would make it about three or four times faster than a normal torpedo and as fast as the world's fastest known underwater missile, the Russian-made VA-111 Shkval, developed in 1995. It was not immediately known if the Hoot was based on the Shkval.

The new weapon gives Iran "superiority" against any warship in the region, Fadavi said, in a veiled reference to U.S. vessels in the Gulf. It was not immediately clear whether the torpedo can carry a nuclear warhead.

Cmdr. Jeff Breslau, spokesman for the U.S. 5th Fleet based on the tiny Arab island nation of Bahrain in the Gulf, said no special measures were taken in reaction to the Iranian war games, even after the latest missile test.

He would not comment on whether the new torpedo represents a threat to American forces in the region.

"In general terms, no matter where we operate in the world, we're aware of other capabilities that exist and of other countries that aren't as friendly to the U.S., and we pay attention to those capabilities," he said.

The U.S. and Iranian navies have had brush-ups during the past ¡ª during the "Tanker War," when U.S. warships moved into the Gulf to guard oil tankers.

In 1988, the frigate USS Samuel B. Roberts was badly damaged by an Iranian mine. In response, the U.S. Navy launched its largest engagement of surface warships since World War II. Two Iranian ships were destroyed, and an American helicopter was shot down, killing the two pilots.

Iran is now trying to show its strength amid worries of U.S. military action over its nuclear program, which Washington says aims to produce nuclear weapons. Iran denies the accusation, saying it intends only to generate electricity.

The U.N. Security Council has demanded Iran give up uranium enrichment, a crucial part of the nuclear process. Washington is pressing for sanctions if Tehran continues its refusal to do so, though U.S. officials have not ruled out military action as an eventual option, insisting they will not allow Iran to gain a nuclear arsenal.

Iran's president, Mahmoud Ahmadinejad, has warned that the United States will "suffer" if it takes action against its nuclear program. Some have seen that as a threat to increase militant action in the region or turn to the oil weapon, though Iranian oil officials have ruled out any squeeze in supplies.

Iran, which views the United States as an arch foe and is concerned about the U.S. military presence in neighboring Iraq and Afghanistan, says the maneuvers aim to develop the Guards' defensive capabilities.

The United States and its Western allies have been watching Iran's progress in missile capabilities with concern. Iran already possesses the Shahab-3 missile, capable of carrying a nuclear warhead and hitting U.S forces in the Middle East.

The upgraded version of the ballistic Shahab-3 missile can travel about 1,200 miles, putting Israel within easy range.

Fadavi said Sunday's torpedo test was the outcome of six years of hard work at the Iranian Aerospace Industries, affiliated with the Defense Ministry.

More than 17,000 Revolutionary Guards forces are taking part in the weeklong maneuvers in the Gulf.

On Sunday, guards paratroops practiced a drop in an attack on a mock enemy position, and warships, jet fighters, helicopters and sophisticated electronic equipment were used in other exercises.

The television report said Sunday's war games included measures to respond to electronic jams caused by a mock enemy.

Iran has routinely held war games over the past two decades to improve its combat readiness and test locally made equipment such as missiles, tanks and armored personnel carriers.

Iran launched an arms development program during its 1980-88 war with Iraq to compensate for a U.S. weapons embargo. Since 1992, Iran has produced its own tanks, armored personnel carriers, missiles and a fighter plane.