Iran has further scaled back its commitments to the 2015 nuclear deal by raising its enrichment levels beyond what was agreed in the deal, according to the United Nations' nuclear watchdog, which yesterday confirmed claims from local media.

"International Atomic Energy Agency Director General Yukiya Amano has informed the IAEA Board of Governors that Agency inspectors on July 8 verified that Iran is enriching uranium above 3.67%," an IAEA spokesman said, according to Euronews.

A report to member states obtained by Reuters said the agency had verified the enrichment level using online enrichment monitors and samples had also been taken on Monday for analysis.

IRNA news quoted atomic agency spokesperson Behrouz Kamalvandi on Monday as saying the 3.67% enrichment level agreed in the deal had been breached.

He later told the semi-official ISNA news agency that enrichment had in fact reached 4.5%.

At a news conference on Sunday, senior Iranian officials said Tehran would keep reducing its commitments every 60 days, unless signatories of the pact moved to protect it from US sanctions, but they left the door open to diplomacy.

The announcement signals a growing challenge to escalating US sanctions pressure.

According to Bloomberg, European powers urged Iran to reverse its latest decision to breach the levels of uranium enrichment under the 2015 nuclear accord but stopped short of threatening sanctions.

The U.K. and the European Union said they were concerned about Iran’s move to abandon uranium enrichment restrictions. Both said they’re in contact with other parties to the accord regarding next steps.

Meanwhile, China criticized the US on Monday for “bullying” Iran, saying the reintroduced sanctions were the cause of the crisis.

Chinese Foreign Ministry spokesperson Geng Shuang said: "The maximum pressure of the United States on Iran is the root cause of the crisis concerning the Iran nuclear issue,” according to Xinhua.