Iran on Sunday condemned, what it called, nuclear threats by the United States, and vowed to lodge a complaint to the United Nations against Washington.

Iran's Supreme Leader Ayatollah Ali Khamenei denounced what he termed threatening words against Iran by U.S. President Barack Obama in the country's new nuclear strategy, the semi-official Fars news agency reported.

Referring to recent Obama's remarks implying using nuclear weapons against Iran, Khamenei said such words are "disgraceful and harmful to the Americans," the report said.

Such words are really strange, for "in the 21st century which is the century of defending human rights and fighting terrorism, the president of a country threatens (another country) with an atomic attack," Khamenei said, adding "the world should not overlook such words."

Addressing a group of Iran's high-ranking military officers in Tehran, Iran's supreme leader also called for "full military and spiritual readiness" of the Iranian armed forces against threats.

Iran's parliament speaker Ali Larijani joined the chorus, criticizing the new U.S. nuclear strategy, pointing out that it runs counter to the Nuclear Non-Proliferation Treaty (NPT), local satellite Press TV reported.

"The United States has announced it will not use nuclear weapons except in extreme circumstances. It has also pledged not to use atomic bombs against NPT members, except Iran and North Korea," Larijani was quoted as saying by the Iranian network.

"And they call this a 'new' nuclear arms strategy. Just take a look at how many contradictory issues are embedded in this policy," he said without elaborating.

As a countermeasure by Iran against the U.S. strategy, Iranian Foreign Ministry spokesman Ramin Mehman-Parast announced that Tehran plans to lodge a formal complaint to the United Nations over the U.S. threatening remarks.

"We will submit our formal complaint against this kind of threats to the United Nations," Mehman-Parast said in an interview with the semi-official Fars news agency.

"Such remarks prove that the countries which possess nuclear arms are the greatest threat to the global security," he said.

"Our military and law enforcement forces enjoy the necessary means and equipment to defend the country and deter attacks," Mehman-Parast was quoted as saying.

On Tuesday, the Obama administration unveiled its long- anticipated new nuclear strategy, promising to reduce the role of nuclear weapons in U.S. national security strategy while reaffirming extended deterrence commitments to its allies.

The U.S. will not use or threaten to use nuclear weapons against non-nuclear weapon states that are parties to the nuclear Non-Proliferation Treaty, Defense Secretary Robert Gates said in a joint briefing with Secretary of State Hillary Clinton and Secretary of Energy Steven Chu on the newly released strategy, known as Nuclear Posture Review.

Speaking in a statement released shortly after Gates unveiled the Nuclear Posture Review, Obama hailed the release of the new nuclear strategy, saying preventing nuclear proliferation and nuclear terrorism is at the top of U.S. nuclear agenda for the first time.

These remarks indicate that countries like Iran and the Democratic People's Republic of Korea that had violated or renounced the treaty would remain on the potential target list of U.S. nuclear forces.

A day later, Iranian Foreign Minister Manouchehr Mottaki dismissed the new U.S. nuclear strategy as "propaganda" and urged Washington to fulfill its promise on nuclear disarmament.

Also, Iran's President Mahmoud Ahmadinejad said that the new U. S. nuclear policy was signed under the pressure of Israel. "Obama signed the new nuclear policy under the pressure of Israeli lobby groups."