Iran's Islamic Revolutionary Guards Corps (IRGC) test-fired several ballistic missiles Tuesday, state television said, challenging a United Nations resolution and drawing a threat of a diplomatic response from the United States.

Two months ago, Washington imposed sanctions against businesses and individuals linked to Iran's missile program over a test of the medium-range Emad missile carried out in October 2015.

U.S. State Department spokesman Mark Toner said Washington would review the incident and, if it is confirmed, raise it in the U.N. Security Council and press for an "appropriate response."

A U.N. resolution calls on Iran not to test any missile capable of carrying a nuclear warhead.

"We also continue to aggressively apply our unilateral tools to counter threats from Iran's missile program," Toner added in a possible reference to additional sanctions.

Brig. Gen. Amir Ali Hajizadeh, commander of the IRGC's aerospace arm, said sanctions would not stop Iran developing its ballistic missiles, which it regards as a cornerstone of its conventional deterrent.

"Our main enemies are imposing new sanctions on Iran to weaken our missile capabilities … But they should know that the children of the Iranian nation in the Revolutionary Guards and other armed forces refuse to bow to their excessive demands," the IRGC's website quoted Hajizadeh as saying.

Underground Silo 

A state television report showed a missile being fired from a fortified underground silo at night. The presenter said it was a medium-range Qiam-1 missile, and the test took place in the early hours of Tuesday.

The report said the Revolutionary Guards had fired several missiles from silos across the country, though it showed footage only of one. "The missiles struck a target 700 km away," Hajizadeh said.

State-run Press TV had earlier shown footage of the Emad missile, Iran's most advanced model under development, being fired. However, that footage appeared to be of the earlier October launch that triggered the U.S. sanctions.

The United Nations said the October test, which took place after Iran reached a nuclear deal with world powers in July, violated Security Council Resolution 1929, which barred Iran from undertaking any work on nuclear-capable ballistic missiles.

That resolution expired when the nuclear deal was implemented in January, but a new resolution then came into force under which Iran is "called upon" not to undertake any work on missiles "designed to" deliver nuclear weapons.

A French diplomatic source said the tests, if confirmed, would constitute a violation of the new U.N. resolution.

"The design by Iran of missiles capable of carrying nuclear weapons would contravene U.N. Security Council resolution 2231, which calls on Iran to abstain from all activity in this field," the French source said.

Iran always denied any link between its ballistic missiles and its disputed nuclear program, which is now subject to strict limitations and checks under the nuclear deal.

Tuesday's test is intended "to show Iran's deterrent power and also the Islamic Republic's ability to confront any threat against the [Islamic] Revolution, the state and the sovereignty of the country," the IRGC's official website said.

While any missile of a certain size could in theory be used to carry a nuclear warhead, Iran says the Emad and other missiles are for use as a conventional deterrent. Recent work has focused on improving the missiles' accuracy, which experts say will make them more effective with conventional warheads.