Iran has denied that its Revolutionary Guards launched rockets near a US aircraft carrier in the Gulf and condemned US plans for new sanctions over its ballistic missile program.

Key points: Iran describes claims it fired rockets as "psychological warfare"

Iran describes claims it fired rockets as "psychological warfare" US media says Iran conducted "unsafe" live-fire exercise near US aircraft-carrier

US media says Iran conducted "unsafe" live-fire exercise near US aircraft-carrier Iran condemns "arbitrary and illegal" planned sanctions over ballistic missile program

The dispute comes after Iran and six world powers, including the United States, reached a deal in July that will remove certain US, European Union and UN sanctions on Tehran in exchange for Iran accepting curbs on its nuclear program.

"The naval forces of the Guards have not had any exercises in the Strait of Hormuz during the past week and the period claimed by the Americans for them to have launched missiles and rockets," the Revolutionary Guards website quoted Ramezan Sharif, the Guard's spokesman, as saying.

"The publication of such false news under the present circumstances is akin to psychological warfare," Sharif said.

NBC News, citing unnamed US military officials, said the Guards were conducting a live-fire exercise and the US aircraft-carrier Harry S. Truman came within about 1,500 yards of a rocket as it entered the Gulf with other warships.

In Washington, Commander Kyle Raines said the action was "highly provocative, unsafe and unprofessional."

Several Revolutionary Guard vessels fired the rockets "in close proximity" of the warships and nearby merchant traffic "after providing only 23 minutes of advance notification," said Raines, spokesman for the US Central Command.

Iranian and US forces have clashed in the Gulf in the past, especially during the Iran-Iraq war in the 1980s after the 1979 Islamic revolution.

Diplomats have held out hope the deal over Iran's disputed nuclear program could ease decades of mistrust and reduce tensions in the Middle East.

The West has long suspected the program was aimed at creating a nuclear bomb, something denied by Iran, which sent a shipment of low-enriched uranium materials to Russia this month as part of the deal.

But ahead of the formal easing of international sanctions on Tehran set for the beginning of 2016, tensions have mounted.

Hardliners in Iran have carried out a wave of arrests of activists they accuse of promoting Western "infiltration," while the United States passed a law restricting visa-free travel rights for people who have visited Iran or hold dual Iranian nationality, a measure Iran has called a breach of the deal.

US government 'preparing sanctions'

Iran's Foreign Ministry spokesman Hossein Jaber Ansari condemned as "arbitrary and illegal" US plans for new sanctions on international companies and individuals over Iran's ballistic missile program.

Iran and six world powers reached a deal in July that will remove certain sanctions on Tehran. ( Reuters: Raheb Homavandi )

"As we have declared to the American government ... Iran's missile program has no connection to the (nuclear) agreement," state television quoted Mr Ansari as saying.

"Iran will resolutely respond to any interfering action by America against its defensive programs."

In Washington, sources familiar with the situation said the US government was preparing the sanctions, which the Wall Street Journal said would target about 12 companies and individuals in Iran, Hong Kong and the United Arab Emirates for their suspected role in developing Iran's missile program.

The newspaper later qualified its story, saying the Whitehouse had delayed imposing the financial sanctions and there was no definitive timeline for when they would be imposed.

A team of UN sanctions monitors said in a confidential report seen by Reuters on December 15 that Iran tested a rocket on October 10 capable of delivering a nuclear warhead, which Iran maintains was a convention missile.

US officials have said the Treasury Department retains a right under the nuclear agreement to blacklist Iranian entities suspected of involvement in missile development.

Supreme Leader Ayatollah Ali Khamenei has said such new penalties would nullify the nuclear accord.

"There may actually be a link between the accusations made by the United States (about the Gulf incident) and the new sanctions," Mohammad Marandi, a Tehran University professor, told state-run PressTV.

"The regime in Washington is trying to reimpose these sanctions by other means."

Reuters