An Iranian constitutional watchdog has approved a law requiring the government to suspend United Nations inspections of the country’s nuclear facilities and step up uranium enrichment beyond the limit set under the 2015 nuclear agreement between Tehran and world powers if sanctions are not eased in one month.

The Guardians Council approved the legislation on December 2, a day after it was passed in parliament in what was seen as a show of defiance after the killing of a prominent Iranian nuclear scientist last week.

Iranian President Hassan Rohani criticized the law as “harmful” to diplomatic efforts aimed at restoring the 2015 nuclear deal and easing U.S. sanctions.

The stance of Supreme Leader Ayatollah Ali Khamenei, who has the last word on all strategic decisions made by Iran, is not publicly known.

The 2015 nuclear agreement scrapped sanctions against Iran in return for curbs to the country’s nuclear program.

But the United States unilaterally withdrew from the deal in 2018, and started imposing crippling sanctions on Iran, and Tehran has gradually reduced its compliance with the accord in response.

However, inspectors of the UN nuclear watchdog, the International Atomic Energy Agency (IAEA), continue to monitor Iranian nuclear sites as part of the 2015 pact.

Under the new law, the government is required to suspend IAEA inspections if Western powers that are still signatories to the 2015 nuclear accord — Britain, France, Germany, China, and Russia — do not reestablish Iran’s access to world banking and oil markets within a month.

It also calls for Iran to resume enriching uranium to 20 percent purity “for peaceful uses.”

Iran currently enriches a growing uranium stockpile up to around 4.5 percent, above the deal’s 3.67 percent cap, but below the 20 percent Iran had achieved before and the 90 percent purity considered weapons-grade.

Tehran has always denied pursuing nuclear weapons, saying its nuclear program was strictly for civilian purposes.

The bill was first tabled in parliament in the summer but gained new momentum after the killing of Mohsen Fakhrizadeh, who was at the heart of the country’s past covert nuclear program, on the outskirts of Tehran on November 27.

No one has claimed responsibility, but Iranian officials have blamed the killing on Israel, an exile opposition group, and Saudi Arabia.

Israeli officials have declined to comment on the killing, while the Iranian opposition group and Saudi Arabia have also denied any involvement.