(AP) — Iran has started removing 27 surveillance cameras from nuclear sites across the country, the head of the U.N. atomic watchdog said Thursday, warning this could deal a “fatal blow” to the tattered nuclear deal as Tehran enriches uranium closer than ever to weapons-grade levels.

The development comes a day after the International Atomic Energy Agency’s board of governors censured Tehran for failing to provide “credible information” over man-made nuclear material found at three undeclared sites in the country.

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It also follows months of deadlocked over stalled talks aimed at restoring the Islamic Republic’s 2015 nuclear deal with world powers.

Tensions remain high across the wider Middle East over the accord’s collapse as U.S. sanctions and rising global food prices choke Iran’s ailing economy, putting further pressure on its government and its people.

“This, of course, poses a serious challenge to our ability to continue working there,” warned Rafael Mariano Grossi, the IAEA’s director-general.

He added that if an agreement cannot be reached to restore the cameras in three to four weeks, “this would be a fatal blow” to Iran’s tattered nuclear deal.

Already, Grossi warned that without the cameras, Iran could make centrifuges and divert them to unknown locations.

Iran did not immediately acknowledge it was removing the 27 cameras, though it earlier threatened it could take more punitive steps.

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State media aired footage Thursday of workers disconnecting two IAEA cameras from power.