DUBAI - Iran said on Sunday it could quit a treaty against the spread of nuclear weapons after the United States tightens sanctions, while an Iranian general said the US Navy was interacting as before with an elite military unit blacklisted by Washington.

Tensions between Tehran and Washington have risen since the Trump administration withdrew last year from a 2015 international nuclear deal with Iran and began ratcheting up sanctions.

Earlier this month, the United States blacklisted Iran's elite Revolutionary Guards (IRGC) and demanded buyers of Iranian oil stop purchases by May or face sanctions.

"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," state broadcaster IRIB's website quoted Foreign Minister Mohammad Javad Zarif as saying.

Iran has threatened in the past to leave the NPT, as US President Donald Trump moved to scrap the 2015 deal with world powers.

President Hassan Rouhani and some senior military commanders have threatened to disrupt oil shipments from Gulf countries if Washington tries to strangle Tehran's oil exports.

Iran has also threatened to pull out of the 2015 deal unless European powers enable it to receive economic benefits.

The Europeans have said they would help companies do business with Iran as long as it abides by the deal, but Tehran has criticized what it sees as the slow pace of progress on a promised payment mechanism for Iran-Europe trade.

"The Europeans have had a year but unfortunately they have not taken any practical measures," Zarif told IRIB.

Reuters