Iran has warned it would tear up much of the international monitoring of its nuclear activities next week if the U.S. doesn’t lift economic sanctions, in a fresh bid to pressure the Biden administration to drop the sanctions. Iran had already indicated it would restrict the access of United Nations atomic agency inspectors starting later this month if sweeping U.S. sanctions imposed on the country since 2018 by the Trump administration weren’t lifted.

On Monday, its ambassador to the International Atomic Energy Agency confirmed on Twitter he had sent a letter to the agency setting out the restrictions. He said they would take effect on Feb. 23. A confidential report by the IAEA on Tuesday, seen by The Wall Street Journal, detailed measures that would severely limit the ability of the agency to oversee Iran’s nuclear work.

The monitoring of Iran’s nuclear facilities was the last major component of the 2015 nuclear deal that Tehran had abided by. Iran started to breach key aspects of that agreement in July 2019 in retaliation for the U.S. withdrawal from the agreement and imposition of sanctions on Tehran.

Iran had said publicly it would cease to apply the Additional Protocol next week, an arrangement that allows IAEA inspectors broad access to facilities other than declared nuclear sites.

However, according to the report, Iran sent the agency a letter on Monday, saying it would move to end daily access to its main nuclear sites. It threatened to remove “modern technologies” like electronic seals that ensure Iran is not accessing banned equipment and online monitoring of Iran’s enrichment.

The IAEA concluded that these steps would have a “serious impact” on its monitoring of Iran’s activities, according to the report that was sent to member states.

Iran gave itself some wiggle room on how quickly it implements the restrictions, according to the report, saying in a letter it sent the agency on Monday, that it expected the agency to prepare for its restricted access “in due time.”