A man walks in front of a tower of the Kremlin and the Russian Foreign Ministry building in central Moscow on September 10, 2020. (YURI KADOBNOV / AFP)

MOSCOW - The Russian Foreign Ministry said Tuesday that the United States is responsible for Iran's recent decision of enriching uranium to 20 percent.

The Iranian move was "a deviation" from the Joint Comprehensive Plan of Action (JCPOA), commonly known as the Iran nuclear deal, but the "root cause" of such deviations is the "systematic gross violations" of international obligations by the United States, the ministry said in a statement.

The Iranian move was "a deviation" from the Joint Comprehensive Plan of Action (JCPOA), commonly known as the Iran nuclear deal, but the "root cause" of such deviations is the "systematic gross violations" of international obligations by the United States, the Russian Foreign Ministry said

The United States, contrary to Article 25 of the UN Charter, does not comply with the UN Security Council Resolution 2231 and deliberately creates obstacles to its implementation for other countries, the ministry said.

According to Moscow, enriching uranium to 20 percent has nothing to do with Iran's compliance with the Treaty on the Non-Proliferation of Nuclear Weapons (NPT).

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All material enriched up to 20 percent is under the control of the International Atomic Energy Agency, which does not record its switch to the use for undeclared purposes that go against the NPT, the statement read.

The Atomic Energy Organization of Iran announced late on Monday that the 20-percent enriched uranium had started at its Fordow facility and had reached the stability level.

In May 2018, US President Donald Trump pulled his country out of the Iranian nuclear deal and reimposed harsh sanctions against Iran. In response, Tehran has gradually dropped some of its JCPOA commitments since May 2019.  

Meanwhile, the European Union (EU) is "highly concerned" over Iran's decision to start enriching uranium with 20 percent purity, a spokesperson said on Tuesday.

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Peter Stano, a spokesperson for the bloc's external action service, said at the European Commission's daily briefing that Iran's decision was "regrettable."

Stano noted that the move would have serious implications on the NPT as it is "in breach with Iran's nuclear commitments."

However, Iranian Foreign Minister Javad Zarif tweeted on Monday that the action "conforms fully" with the JCPOA, and affirmed that the measures were "fully reversible upon FULL compliance by ALL."

Stano underlined that all parties were willing to maintain JCPOA and the EU would be working to make sure that all parties were to respect the nuclear deal.

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Also on Tuesday, Chinese Foreign Ministry spokesperson Hua Chunying said it is imperative for all parties to push the United States to unconditionally return to JCPOA as soon as possible and lift all relevant sanctions.