Iran says leaving nuclear treaty one of 'numerous' options

In other news, an Iranian general said the US Navy had not changed its interaction with the Iranian Revolutionary Guard despite the elite military unit being blacklisted by Washington.

Tensions between Iran and the United States have risen since President Donald Trump withdrew from a landmark 2015 nuclear accord with world powers last year and reimposed crippling sanctions. The deal granted Iran relief from sanctions in return for limitations on its nuclear programme.

"The Islamic Republic's choices are numerous, and the country's authorities are considering them ... and leaving NPT (nuclear Non-Proliferation Treaty) is one of them," said Foreign Minister Mohammad Javad Zarif according to Reuters.

This is not the first time Iran has threatened to leave the NPT.

This month, the Trump administration blacklisted Iran's Revolutionary Guard as a "terrorist organisation" and announced it would not renew sanctions waivers for countries that import Iranian oil.

The designation, which took effect April 15, is part of a broader administration effort to increase pressure on Tehran. The Revolutionary Guard is the first agency of a foreign government ever to be designated a foreign terrorist organisation by the US.

Despite the blacklisting, Iran's armed forces chief of staff said the Revolutionary Guard  - entrusted with security in Gulf waters and the Strait of Hormuz for Iran - had not observed any change in US military behaviour.

US ships continued to respond to the Revolutionary Guard on the Strait of Hormuz on Saturday, said Major General Mohammad Baqeri on Sunday according to Reuters.

The Revolutionary Guard has previously threatened to shut down the Strait of Hormuz, a major shipment channel in the Gulf, if barred from using it. "If our oil does not pass, the oil of others shall not pass the Strait of Hormuz either," Baqeri reiterated.

Carrying one third of the world's seaborne oil every day, the Strait of Hormuz links the Middle East to the world market.

Europe has tried to keep the 2015 NPT alive through developing a special payment mechanism that curtails US sanctions. 

Iran has also threatened to pull out of the treaty unless Europe is also to provide it with economic benefits. The Iranian economy has suffered under increased US sanctions.

Agencies contributed to this report.

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