DUBAI, United Arab Emirates — Construction is underway at the Natanz nuclear facility in Iran, satellite imagery released Wednesday by San Francisco-based Planet Labs reveals, against the backdrop of new sanctions imposed on the country by the U.S. and the steady disintegration of the 2015 nuclear deal. First reported by the Associated Press, the images show a road being built from August onward to the south of the city of Natanz, in Iran’s central western Isfahan province, toward the enrichment facility along with what appears to be construction materials. Analysts interviewed by the wire agency believe the photos capture excavation work and a potential tunnel into the surrounding mountains. U.N. nuclear watchdog the International Atomic Energy Agency (IAEA) confirmed to the AP that Iran is constructing an “underground advanced centrifuge assembly plant.”It also told the AP that IAEA inspectors were aware of the construction and that Iran had previously informed them of it, which suggests it does not violate the parameters of the 2015 deal. Also known as the JCPOA, the Obama-era deal signed by the U.S., Iran, Russia, China and EU states lifted international sanctions on Iran in 2015 in exchange for curbs to its nuclear program. A general view of the Natanz nuclear enrichment facility, is seen on April 9, 2007, 180 miles south of Tehran, Iran.Majid Saeedi/Getty ImagesThe Natanz uranium enrichment site, a large part of which is underground, suffered a fire in July of this year. Iranian officials allege the fire was a sabotage attack, and one they say caused damage significant enough to slow the development of advanced uranium enrichment centrifuges. The director of Iran’s atomic energy agency in August announced that the above-ground part of the facility would be rebuilt in the mountains around Natanz. IAEA director-general Rafael Grossi told AP that the construction “means that they have started, but it’s not completed,” adding that “it’s a long process.” Iran’s Atomic Energy Organization did not reply to a CNBC request for comment. Tehran maintains that its nuclear development is solely for peaceful purposes, while the Trump administration and some of its allies, including Israel, have long accused the country of pursuing a nuclear bomb. The slow death of the 2015 nuclear dealPresident Donald Trump’s administration withdrew from the Iranian nuclear deal in 2018, reimposing sweeping sanctions on Tehran that helped cripple its economy. Iran has responded with gradual breaches of the deal’s limits, including surpassing the agreed limit on its enriched uranium stockpile, in response to U.S. actions. IAEA inspectors nonetheless continue to have access to Iran’s nuclear sites, one of the stipulations of the deal, which its non-U.S. signatories have scrambled to keep alive. International Atomic Energy Agency (IAEA) inspectors (2nd-3rd L) and Iranian technicians at the Natanz nuclear power plant, Iran.Kazem Ghane | AFP | Getty ImagesTensions between the countries have risen sharply since a spate of sabotage attacks in Gulf waters last year that Washington blames on Iranian operatives but that Tehran denies, and since the U.S. killing by drone strike of top Iranian commander Qasem Soleimani in January of this year. Relations may yet improve in the aftermath of the upcoming U.S. presidential election, depending on who takes the White House. The JCPOA’s fate might not be sealed, political analysts say, as a potential Joe Biden administration would likely pursue rehabilitating the deal in some form.