Iran nuclear deal must be revived in weeks: IAEA

"It is clear that we don’t have many months ahead of us. We have weeks," Grossi said in an interview for the Reuters Next conference.

Iran resumed 20% uranium enrichment at the Fordow underground nuclear facility earlier this month, again breaching the nuclear pact with major powers and possibly complicating efforts by U.S. President-elect Joe Biden to rejoin the deal.

Its parliament passed a law in November that obliges the government to halt inspections of its nuclear sites by the International Atomic Energy Agency and step up uranium enrichment if sanctions are not eased.

An Iranian lawmaker said on Jan. 9 said it would give the new U.S. administration until Feb. 21 to reverse sanctions.

"I must take it seriously because it's the law," Grossi said, adding that he believed the government intended to implement it.

Grossi said Iran was progressing "quite rapidly" in 20% enrichment and that based on estimations it would be able to reach about 10 kilograms a month at its facility in Fordow.

Tehran started violating the accord in 2019 in a step-by-step response to Trump's withdrawal from it in 2018 and the reimposition of U.S. sanctions lifted under the deal.