Iranian lawmakers protested on Monday against Tehran's decision to permit "necessary" monitoring by the UN nuclear watchdog for up to three months, saying the move broke a law mandating an end to the agency's snap inspections this week.
"The government has no right to decide and act arbitrarily," said Mojtaba Zolnour, chairman of the parliament's national security committee, according to Iranian state media.
"This arrangement is an insult to the parliament."
Iran has been gradually breaching terms of a 2015 nuclear pact with world powers since then US President Donald Trump withdrew from it in 2018 and reimposed sanctions. The pact aims to keep Iran at arm's length from being able to make nuclear arms, which Tehran says it has never wanted to build.
Under the deal, Tehran agreed to implement the Additional Protocol, which allows the International Atomic Energy Agency (IAEA) to carry out short-notice inspections at locations not declared to it.
But to pressure President Joe Biden's administration to lift sanctions, Iran's hardline-dominated parliament passed a law last year obliging the government to end implementation of the Protocol from Tuesday if US sanctions are not lifted.
To create room for diplomacy, the UN nuclear watchdog on Sunday reached a deal with Iran to cushion the blow of Iran's reduced cooperation with the agency and its refusal to permit short-notice inspections.
Under the new agreement, while the number of the IAEA inspectors on the ground will remain the same, Iran has said it will withhold footage recorded by cameras at some of its facilities from the IAEA for the time being, Iranian authorities said.
Iran has not said which cameras at which facilities, but the Additional Protocol Iran is scrapping does generally extend IAEA monitoring to some activities such as uranium mining.
If Washington lifts the sanctions in that period of up to three months, Iran's IAEA envoy Kazem Gharibabadi tweeted, Iran will share the data with the agency.
"Otherwise the data will be destroyed by Tehran forever," Gharibabadi said on Twitter.
But several prominent lawmakers criticised the agreement, accusing the government of "bypassing the law".
The IAEA, in a statement on Sunday, said it would continue "necessary verification and monitoring activities for up to three months", without specifying what those activities are.
However, Iran's foreign ministry on Monday said Tehran would continue implementing the Comprehensive Safeguards Agreement, its core obligations to the agency that allow for monitoring of its declared nuclear facilities.
Both Tehran and Washington say they are willing to come back into compliance with the badly eroded nuclear deal if the other side moves first.