Iran announced on Sunday it would abandon limitations on enriching uranium, taking a further step back from commitments to a 2015 nuclear deal with six major powers.

Under the landmark Iran nuclear deal, known as the Joint Comprehensive Plan of Action (JCPOA), Tehran agreed to curb its nuclear activities in exchange for the lifting of most international sanctions.

However, the Trump administration unilaterally abandoned the deal on May 8, 2018, and re-imposed crippling economic sanctions on Iran.

In response, Tehran started to make staged moves every two months to drop its nuclear commitments. Starting last year, Iran exceeded agreed limits to its stockpile of low-enriched uranium and then began enriching uranium.

The Sunday announcement, that comes after the U.S. killing of top Iranian military commander Qasem Soleimani, was the fifth and final step to end its commitments to the landmark 2015 nuclear deal.

"In the fifth step of withdrawing from its commitments, the Islamic Republic of Iran drops the last key restriction under the nuclear deal, namely 'restriction on the number of centrifuges'," IRNA cited the announcement by Iranian government as reading.

Therefore, "Iran's nuclear program will no longer embrace any practical restrictions, including the level and purity of enrichment, the mass of enriched materials and R&D activities," read the announcement.

So far Iran has not gone far over the purity allowed – the deal sets a limit of 3.67 percent – and Iran has stayed around 4.5 percent in recent months, well below the 20 percent it reached before the deal and the roughly 90 percent that is weapon-grade. 

The Iranian government also said that Tehran is ready to re-embrace its nuclear commitments, in case anti-Iran sanctions are removed and its economic interests under the nuclear deal are secured.

"As before, Iran will continue its cooperation with the International Atomic Energy Agency (IAEA)," according to Iran's announcement on Sunday.

"This step is within JCPOA (deal) & all five steps are reversible upon EFFECTIVE implementation of reciprocal obligations," tweeted Iranian Foreign Minister Mohammad Javad Zarif. 

(With inputs from agencies)