TEHRAN, Iran — Iran tested its longest-range missiles today, capping two days of war games meant to show the country is ready for any military threat at a time when it is under intense international pressure to fully disclose its nuclear activities.

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 began Sunday, two days after the U.S. and its allies disclosed that Iran had been secretly developing an underground uranium enrichment facility and warned the country it must open the site to international inspection or face harsher international sanctions.

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.

Alex Vatanka, a senior Middle East analyst at IHS Jane's, said Tehran was conducting missile tests now "to show some muscle, show some strength, and say the game is not over for Iran yet." He noted the upcoming meeting in Geneva. "They felt going into these meetings ... that they needed to have something else to bolster their position, and I think that Iran's Revolutionary Guard showing a bit of military muscle here is part of that," he said.

U.S. Secretary of State Hillary Clinton said she does not believe Iran can convince the U.S. and other world powers at the upcoming meeting that its nuclear program is for peaceful purposes, as Tehran has claimed. She said that puts Tehran on a course for tougher economic penalties beyond the current "leaky sanctions."

Iran also is developing ballistic missiles that could carry a nuclear warhead, but the administration said last week that it believes that effort has been slowed. 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 ballistic missiles.

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.