The Iranian flag flutters in front the International Atomic Energy Agency (IAEA) headquarters in Vienna, Austria July 10, 2019. Photo: REUTERS/Lisi Niesner

Iran said on Monday it will block snap inspections by the UN nuclear watchdog from next week if other parties to the 2015 nuclear deal do not fulfill their obligations, a challenge to US President Joe Biden’s hope of reviving the accord.

“If others do not fulfill their obligations by Feb. 21, the government is obliged to suspend the voluntary implementation of the Additional Protocol,” Foreign Ministry spokesman Saeed Khatibzadeh said.

“It does not mean ending all inspections by the UN nuclear watchdog … All these steps are reversible if the other party changes its path and honors its obligations,” he said, alluding to the United States.

The Biden administration aims to return the United States to the nuclear deal, which his predecessor Donald Trump abandoned in 2018. Under the deal, Iran agreed to curbs on its uranium enrichment program in return for the lifting of sanctions.

After Trump quit and reimposed sanctions, Iran began violating some limits in the deal. Washington and Tehran now disagree over how best to restore the accord, with both sides demanding the other side act first to return to compliance.

Despite Iran‘s public hard line that Washington must take the first step, several Iranian officials told Reuters last week that the mounting economic pain of US sanctions may push Tehran to be flexible on terms for restoring the nuclear deal.

Qatari Foreign Minister Sheikh Mohammed bin Abdulrahman Al-Thani said last week Doha was in consultations to help salvage the deal, and Iranian state media said he would meet Iranian counterpart Mohammad Javad Zarif in Tehran on Monday.

“We welcome efforts by friendly countries like Qatar … There have been consultations between Tehran and Doha at various levels,” Khatibzadeh said.

The nuclear deal granted wide-ranging access to the International Atomic Energy Agency to gather information on Iran’s nuclear activities. But under a law enacted last year, Iran‘s government is obliged to revoke that access on Feb. 21 if other parties are not complying with the nuclear deal.

Iran has long denied striving to develop nuclear weapons through uranium enrichment, though its intelligence minister said last week persistent Western pressure could push Tehran to fight back like a “cornered cat” and seek nuclear weapons.

But Khatibzadeh rejected this, citing a religious decree issued in the early 2000s by the Islamic Republic’s top authority, Supreme Leader Ayatollah Ali Khamenei, banning the pursuit of nuclear arms.