TASS, April 28. Iran is considering plans of leaving the Treaty on the Non-Proliferation of Nuclear Weapons as one of the options of responding to tightening US sanctions against the Islamic republic, Iranian Foreign Minister Mohammad Javad Zarif told state television, according to the Mehr news agency.

"The Islamic Republic’s choices are numerous, and the officials are studying them…leaving NPT is one of them," Zarif said on Sunday.

Washington restored sanctions against Iran, including the ban on oil purchases, in November 2018.

The NPT is a multilateral international document drafted by the UN committee on disarmament with the aim of preventing the expansion of the list of countries possessing nuclear weapons and easing the risk of a nuclear conflict. The treaty was approved on June 12, 1968 at the 22nd UN General Assembly session and was signed in London, Moscow and Washington (its three depositaries were Britain, the Soviet Union and the United States). The treaty took effect on March 5, 1970 after 40 countries had ratified it. Currently, 190 countries are parties to the NPT.