Sputnik - Iranian Foreign Minister Mohammad Javad Zarif confirmed earlier that Tehran had stockpiled over 300 kilograms (661 pounds) of enriched uranium in a response to the US withdrawal from the 2015 JCPOA nuclear treaty.

US Secretary of State Mike Pompeo said in an earlier statement that Washington is calling on the international community to immediately impose and enforce a total ban on all Iran activities involving the enrichment of nuclear materials.

In a separate statement, Pompeo claimed on Monday that Tehran "uses its nuclear program to extort the international community".

Earlier in the day, White House spokesperson Sarah Sanders echoed Pompeo's remarks, stressing that a nonproliferation standard for "no enrichment for Iran" must be restored.

"We must restore the longstanding nonproliferation standard of no enrichment for Iran", Sanders said.

Last week, the United States imposed new sanctions against Tehran targeting, in particular, Iranian Supreme Leader Ayatollah Ali Khamenei. Washington also said it was preparing sanctions against Iranian Foreign Minister Mohammad Javad Zarif.

On 8 May, Iran announced it would partially discontinue its voluntary obligations under the 2015 JCPOA nuclear treaty. The decision came a year after US President Donald Trump announced that he was withdrawing the United States from the historic nuclear agreement and reimposing wide-ranging sanctions on Iran.

On the same day, Iran gave the other nuclear deal signatories � China, the European Union, France, Germany, Russia and the United Kingdom � an ultimatum, saying that in 60 days it would reduce some other obligations if the remaining signatories did not shield Tehran from Washington's sanctions.

International Atomic Energy Agency (IAEA) Director General Yukiya Amano confirmed that Iran had exceeded the limit of 300 kilograms (661 pounds) for enriched uranium.

Anger between the US and Iran is significantly escalating Middle East instability. The United States, in particular, has built up its military presence in the region in what US National Security Advisor John Bolton called a clear message to Iran.