Tehran, Iran ? Determined not to budge under pressure, Iran announced new tests of short-range missiles Sunday, and hardline President Mahmoud Ahmadinejad insisted his country had a right to enrich uranium for nuclear power.

The missile tests come as the U.S. Navy is sending a second aircraft carrier to the volatile Persian Gulf. U.S. officials said the USS John C. Stennis, which arrives in Mideast waters in a matter of weeks, is meant as a warning to Iran.

The deployment appeared to alarm some in Iran’s hardline leadership, including a member of a powerful cleric-run body who warned last week that Washington plans to attack, possibly by striking Iranian nuclear facilities. U.S. officials long have refused to rule out any options in the faceoff with Tehran but say military action would be a last resort.

Stressing Iran’s preparedness, state television said the Revolutionary Guards planned to begin three days of testing the short-range Zalzal and Fajr-5 missiles Sunday. It could not be confirmed if the exercise had begun near Garmsar city, about 60 miles southeast of Tehran.

“The maneuver is aimed at evaluating defensive and fighting capabilities of the missiles,” the report quoted an unidentified Guards commander as saying.

Last year, Iran staged three large-scale military exercises to test what it called an “ultra-horizon” missile and the Fajr-3, a rocket that it claims can evade radar and use multiple warheads to hit several targets simultaneously.

Though U.S. officials suggest Iran exaggerates its military capabilities, Washington is concerned about Iranian progress in developing missiles. Some of its missiles are capable of hitting U.S.-allied Arab nations and Israel, which Ahmadinejad has called to be wiped off the map.

The United States, which led military maneuvers of its own in the Persian Gulf in October, also accuses Iran of supporting militants in Iraq’s sectarian bloodshed and is trying to rally Arab allies to isolate the Tehran regime.

Iran’s new maneuvers are the first since the U.N. Security Council imposed sanctions last month over Ahmadinejad’s defiance of its demand that Tehran suspend uranium enrichment. The sanctions ban selling materials and technology that could be used in Iran’s nuclear and missile programs.

The United States and its allies accuse Iran of secretly developing atomic weapons in violation of its treaty commitments. Tehran repeatedly has denied that, saying its program is solely for the peaceful purpose of developing nuclear technology to generate electricity.

A top American diplomat urged Iran on Sunday to resume negotiations on curbing its nuclear program, warning of stepped-up international pressure if diplomacy fails.

Speaking in Israel, Undersecretary of State Nicholas Burns said the limited U.N. sanctions imposed were just the beginning of the global effort to punish the Tehran regime. “Iran is going to have to suffer the consequences of being an international pariah,” he said.

Ahmadinejad has remained defiant, saying Iran has the right to conduct uranium enrichment, a process that can produce fuel for nuclear reactors but also provide material fuel for atomic bombs.