Iran announced it was building a new centrifuge production plant at its Natanz nuclear facility, indicating a possible future restart to enrichment activity following the U.S.’s withdrawal from the 2015 nuclear agreement.

Iran has vowed to limit enrichment of nuclear material to sub-weapons grade levels under the Joint Comprehensive Plan of Action (JCPOA), but the new plant suggests that the country could be bolstering its ability to ramp up nuclear activity should the agreement collapse further, according to the New York Times.

President Donald Trump confirmed that the U.S. would abandon the deal last month, calling it “defective at its core” and reimposing sanctions on Iran’s central bank chief. Trump also warned Iran against restarting its nuclear program, threatening “very severe consequences.” Other signatories, including Germany, France, and the U.K., are now trying to salvage the deal.

Read more: Former Israeli PM: The Iran Deal Was Flawed. But Trump’s Decision Makes the World ‘More Uncertain’

Ali Akbar Salehi, the head of the Atomic Energy Organization of Iran, told Iranian state television that the new centrifuge facility remained “in line with our safeguard commitments” under the deal, according to the Times. In a speech Monday, Ayatollah Ali Khamenei, Iran’s supreme leader, called on the country’s atomic agency to begin preparations to increase uranium enrichment capacity, reports the Tehran Times. Though he reiterated that the country would abide by the accord’s constraints, which limits uranium enrichment to 3.67%.

Iran’s nuclear facilities are regularly monitored by the International Atomic Energy Agency (IAEA) under the 2015 agreement.

It remains unclear if or when the facility will begin making new centrifuges. An IAEA spokesperson said Tuesday that they received a letter from Iran declaring a “tentative schedule” to start production of uranium hexafluoride, the raw material for the centrifuges, the BBC reports.

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Write to Eli Meixler at eli.meixler@time.com.