State television said the powerful Revolutionary Guard, which controls Iran's missile program, successfully tested upgraded versions of the medium-range Shahab-3 and Sajjil missiles. Both can carry warheads and reach up to 1,200 miles (2,000 kilometers), putting Israel, U.S. military bases in the Middle East, and parts of Europe within striking distance.
The missile tests were meant to flex Iran's military might and show readiness for any military threat.
"Iranian missiles are able to target any place that threatens Iran," said Abdollah Araqi, a top Revolutionary Guard commander, according to the semi-official Fars news agency.
Iran conducted three rounds of missile tests in drills that began Sunday, two days after the U.S. and its allies disclosed the country had been secretly developing an underground uranium enrichment facility. The Western powers warned Iran it must open the site to international inspection or face harsher international sanctions.
Iran's Foreign Ministry spokesman Hasan Qashqavi said the missile tests had nothing to do with the tension over the site, saying it was part of routine, long-planned military exercises.
European Union foreign policy chief Javier Solana said he was concerned about the missile tests. He said Iran must immediately resolve issues surrounding its second nuclear enrichment facility with the U.N.'s nuclear agency.
The newly revealed nuclear site has given greater urgency to a key meeting on Thursday in Geneva between Iran and six major powers trying to stop its suspected nuclear weapons program. Solana said those talks are now taking place "in a new context."
Britain said Monday's test further illustrates why Europe and the U.S. have serious concerns about Iran's nuclear intentions, and France called it a provocation.
"This sends the wrong signal to the international community at a time when Iran is due to meet" the six world powers, Britain's Foreign Office said. The six nations are the U.S., Britain, France, Russia, China and Germany.
The nuclear site is located in the arid mountains near the holy city of Qom and is believed to be inside a heavily guarded, underground facility belonging to the Revolutionary Guard, according to a document sent by President Barack Obama's administration to lawmakers.
Although there was no confirmation from the U.S. or Iran, a satellite image provided by DigitalGlobe and GeoEye shows what experts believe to be the site on a military base near Qom. According to defense consultancy IHS Janes, which did the analysis of the imagery, it shows a well-fortified facility built into a mountain about 20 miles (30 kilometers) northeast of Qom, with ventilation shafts and a nearby surface-to-air missile site. The image was taken in September.
Iran's Foreign Ministry, however, gave a different location for the site, saying Monday it was near the village of Fordo, which is about 30 miles (50 kilometers) south of Qom.
Jane's did not offer any immediate comment on the discrepancy. After strong condemnations from the U.S. and its allies, Iran said Saturday it will allow U.N. nuclear inspectors to examine the site.
Israel has trumpeted the latest discoveries as proof of its long-held assertion that Iran is seeking nuclear weapons.
Iran's known industrial-scale uranium enrichment plant is in Natanz.
By U.S. estimates, Iran is one to five years away from having nuclear weapons capability, although U.S. intelligence also believes that Iranian leaders have not yet made the decision to build a weapon.
Iran also is developing ballistic missiles that could carry a nuclear warhead. A U.S. intelligence assessment in May, however, said Iran had slowed work on its long-range ballistic missiles and was instead focusing efforts on short- and medium-range missiles like the Shahab.
That assessment paved the way for Obama's decision to shelve the Bush administration's plan for a missile shield in Europe, which was aimed at defending against Iranian intercontinental ballistic missiles.
Iran is not expected to have such a missile until 2015 to 2020, according to the report, which was described by a U.S. government official on condition of anonymity because the report is classified.
The Sajjil-2 missile is Iran's most advanced two-stage surface-to-surface missile and is powered entirely by solid-fuel while the older Shahab-3 uses a combination of solid and liquid fuel in its most advanced form, which is also known as the Qadr-F1.
Solid fuel is seen as a technological breakthrough for any missile program as solid fuel increases the accuracy of missiles in reaching targets.
Experts say Sajjil-2 is more accurate than Shahab missiles and its navigation system is more advanced.
State media reported tests overnight of the Shahab-1 and Shahab-2 missiles, with ranges of 185 miles (300 kilometers) and 435 miles (700 kilometers) respectively.
That followed tests early Sunday of the short range Fateh, Tondar and Zelzal missiles, which have a range of 120 miles (193 kilometers), 93 miles (150 kilometers) and 130 miles (200 kilometers) respectively.
Iran's last known missile tests were in May when it fired its longest-range solid-fuel missile, Sajjil-2. Tehran said the two-stage surface-to-surface missile has a range of about 1,200 miles (1,900 kilometers) - capable of striking Israel, U.S. Mideast bases and southeastern Europe.