A day after Ahmadinejad inaugurated a heavy-water plant that could be used to produce plutonium, Iran test-fired a sub-to-surface missile in the Persian Gulf. The missile was fired on Sunday during large-scale military exercises, state-run television reported. "The army successfully test-fired a top speed long-range sub-to-surface missile off the Persian Gulf," the Army's Navy commander, Gen. Sajjad Kouchaki, said on television. A brief video clip showed the missile, fired from a submarine, exiting the water and hitting a target on the surface of the water within a kilometer. The test came as part of large-scale military exercises under way throughout the country that began on August 19. Iran has routinely held war games over the past two decades to improve its combat readiness and to test equipment including missiles, tanks and armored personnel carriers. The test comes amid a standoff between Iran and the United States over Teheran's nuclear activities. The Islamic Republic, which views the United States as a foe, is concerned about US military presence in neighboring Iraq and Afghanistan. Iran had also expressed worry about Israeli threats to destroy its nuclear facilities, which the West contends could be used to make a bomb but which Iran insists are for civilian uses only. Kouchaki said the missile, called Thaqeb or Jupiter, was built based on domestic know-how, although outside experts say much of the country's missile technology originated from other countries such as Russia and China. "The guided missile can be fired from all vessels," he said. Iran already is equipped with the Shahab-3 missile, which means "shooting star" in Farsi, and is capable of carrying a nuclear warhead. An upgraded version of the ballistic missile has a range of more than 1,930 kilometers and can reach Israel and US forces in the Middle East. In an advance for Iran's weapons industry, the Thaqeb is the country's first submarine-fired missile that leaves the water to strike its target, adding to Iran's repertoire of weapons that can hit ships in the Gulf. Last year, former Defense Minister Ali Shamkhani said Teheran had successfully tested a solid fuel motor for the Shahab-3, which was considered a technological breakthrough for the country's military. Solid fuel dramatically increases the accuracy of a missile while a liquid fuel missile is not very accurate in hitting targets. Iran's military test-fired a series of missiles during large-scale war games in the Persian Gulf in March and April, including a missile it claimed was not detectable by radar that can use multiple warheads to hit several targets simultaneously. During the April war games, Iran also tested a new land-to-sea missile, the Kowsar, with remote-control and searching systems that cannot be scrambled, as well as a high-speed missile boat that skims above the water and is undetectable by radar. After decades of relying on foreign weapons purchases, Iran's military has been working to boost its domestic production of armaments. Since 1992, Iran has produced its own tanks, armored personnel carriers, missiles and a fighter plane, the government has said. It announced in early 2005 that it had begun production of torpedoes. Iran's arsenal already included several types of torpedos - including the "Hoot," Farsi for "whale," which was tested for the first time in April, capable of moving at some 223 mph, up to four times faster than a normal torpedo. The progress in naval technology has raised concerns in the West that Iran now has a greater array of weapons that can hit oil shipments in the Gulf, through which about two-fifths of the world's oil supplies pass.