The US unilaterally withdrew on May 8, 2018 from the 2015 multilateral deal known as the Joint Comprehensive Plan of Action (JCPOA) under which Iran agreed to halt its nuclear programme in exchange for the lifting of biting sanctions.

Quoting what it called informed sources, ISNA said on Monday that President Hassan Rouhani was likely to announce "step-by-step plans" for "reciprocal measures" on the anniversary of the US pullout.

The rest of the ISNA report was not attributed to any source.

According to the agency, the measures would include the "partial and complete reduction of some of Iran's commitments and restarting part of nuclear activities halted in the framework of the JCPOA."

The report said the measures would be in line with two sections of the accord.

The two sections -- 26 and 36 -- open the way for Iran to cease some or all of its commitments under the deal if the United States or other parties fail to adhere to it, including the reimposition of sanctions.

"This will be Iran's first step toward reacting to the US withdrawal from the JCPOA and also European countries' failure to live up to their commitments," said ISNA.

European Union officials "who have just made unfulfilled promises during the last year" had been unofficially informed of the decision, the agency added.

The three European parties to the deal, Britain, France and Germany, announced the establishment of a special payments system called INSTEX -- Instrument in Support of Trade Exchanges -- in late January as a means to bypass renewed US sanctions.

The trade mechanism meant to the save the deal, however, was dismissed by Iran's supreme leader Ayatollah Ali Khamenei as a "bitter joke" as the difference between EU obligations and their proposals was "as far as the earth is from the sky".

In a move escalating tensions, the US National Security Advisor John Bolton said on Sunday that the United States was sending an aircraft carrier strike group and a bomber task force to the Middle East in a "clear and unmistakable" message to Iran.

The United States was also aiming to put more pressure on the Iranian economy by targeting its petrochemical sales in a new round of sanctions, the Wall Street Journal reported on Thursday.

The White House also ended oil purchase waivers granted to Iran's main customers -- including China, India and Turkey -- meant to cut Iran's access to its main source of foreign currency revenue as part of its campaign of "maximum pressure" against the Islamic republic.