Iran announced partial withdrawal from a 2015 nuclear deal, known as the Joint Comprehensive Plan of Action (JCPOA), a year after President Donald Trump withdrew entirely from the agreement.

In a letter Wednesday, Iran's President Hassan Rouhani informed the existing members of the deal — France, Britain, Germany, Russia and China — on the suspension of its commitments.

“The decision of the high security council to 'stop acting on some of the Islamic Republic of Iran's commitments under the JCPOA was communicated to the heads of state of the countries,” the country's foreign ministry said.

In a statement Wednesday, Iran's Supreme National Security Council (SNSC) said the country would stop abiding with two of its commitments under the deal that limited the nation’s capacity to produce nuclear fuel.

President Rouhani said the country will increase its uranium enrichment and heavy water used in nuclear reactors.

"The Islamic Republic of Iran declares that at the current stage, it does not anymore see itself committed to respecting the limitations on keeping enriched uranium and heavy water reserves," SNSC said in the statement.

The nuclear deal signed by seven nations, including the United States in July 2015, significantly limited Iran’s nuclear ability in return for lifting international sanctions on its oil and financial sectors. The U.S, however, withdrew from the deal in 2018 and re-imposed the sanctions against the country.

Rouhani, on Wednesday, said if the European nations did not compensate for the U.S. sanctions, the country will resume construction of the Arak nuclear reactor that was closed under the deal.

"In case these countries fail to meet Iran's demands, the Islamic Republic of Iran will cease implementation of restrictions on uranium enrichment levels and measures related to the modernization of Arak Heavy Water Reactor as well,” SNSC said, adding, "Once our demands are met, we will resume implementation of the ceased undertakings. Otherwise, the Islamic Republic of Iran will stop compliance with its other undertakings in consequent phases.”

Reminding the countries of its “goodwill” during the nuclear talks, Iran said it is now in their hands to adopt serious measures to protect the deal.

"The door of diplomacy will not remain open for a long time and the U.S. and other members remaining under the nuclear deal are fully responsible for failure of the nuclear deal and any possible consequences," the statement said.

In December, Ali Akbar Salehi, the head of Atomic Energy Organization of Iran, warned if the JCPOA members did not remain committed to the deal, Iran would restore 20-percent uranium enrichment.

“I would like to warn that this is not a bluff; I have kept my word whenever I’ve said something. Now I’m emphasizing once again that if the establishment wants, we can easily return to the 20-percent enrichment, and meet the country’s needs at any level and volume,” he had said.