Iran announced Sunday that it will no longer comply with any commitments under the 2015 nuclear deal signed with several world powers.
"By taking the fifth step in reducing its obligations, Iran is abandoning the last key practical limitation under the Joint Comprehensive Plan of Action, which deals with the number of centrifuges,” the government said in a statement.
The government noted, however, that it will continue to work with the International Atomic Energy Agency (IAEA).
It added that if U.S. sanctions are lifted and benefits are provided, Tehran is ready to return to the agreement.
The decision comes after Qasem Soleimani, the head of Iran's elite Quds force, was killed early Friday in a U.S. airstrike in Baghdad.
Soleimani's death has led to a dramatic escalation in tensions between the U.S. and Iran.
Iran’s Supreme Leader Ali Khamenei, who bestowed the country's highest honor on Soleimani last year, has vowed "severe retaliation" in response to his killing.
Soleimani was the long-time commander of the Quds Force, a unit of the Islamic Revolutionary Guards Corps.
The Quds Force, which was designated a terror group by the U.S., is estimated to have 20,000 members.
The Iran nuclear accord, also known as the Joint Comprehensive Plan of Action (JCPOA), was signed in 2015 between Iran and Russia, China, France, the U.K. and the U.S. plus Germany.
Tensions had been rising between the U.S. and Iran since May 2018, when Washington unilaterally withdrew from the landmark deal.
The U.S. has since embarked on a diplomatic and economic campaign to put pressure on Iran in order to renegotiate the agreement.
As part of its campaign, the U.S. has re-imposed sanctions on exports of Iranian crude oil, which have severely affected Iran’s economy.
By Muhammet Kursun in Tehran
Additional reporting and writing by Dilara Hamit