Mystery fire at Iranian nuclear facility is the latest in a series of unexplained incidents

This satellite image from Planet Labs Inc. shows the substantial damage done by an explosion and a fire at an advanced centrifuge assembly plant at Iran's Natanz nuclear site.

(CNN)It is the world's most scrutinized shed. Exactly what happened to an outer building at an Iranian nuclear facility means both everything and nothing, as Tehran grapples with protecting its regional clout during the twin ravages of the coronavirus and US sanctions.

The Natanz nuclear plant lost a building when fire tore through it at 2:06 a.m. local time Thursday. Satellite images beefed up the photos from ground level that slowly led Iranian officials to switch from calling the damage at the facility "limited" to "significant."
The plant has a florid history: It was the target of Israel's Stuxnet cyber attack in 2010, an attack experts believe was carried out by Israel and the United States, and a focus of the uranium enrichment activity Iran has recently restarted at a higher level since the JCPOA (or nuclear deal) finally collapsed last year. This makes its even partial damage hard to simply dismiss as a broken generator in the summer heat.
    The fire came in the middle of a series of unexplained incidents at other facilities. A huge blast hit near the town of Parchin and its military complex last month. Another explosion hit the Zargan power plant in Ahvaz over the weekend and hours later, a chlorine gas leak made dozens ill in southeast Iran. There is such a thing as coincidence, and sanctions mean maintenance issues can be more frequent. But the pattern just added to the speculation around Natanz.
    Iran's on-the-record response -- which admitted nothing bar claiming to know the "main cause" -- perhaps was the most telling, that it would detail the cause when it suited. You might assess that a government dealing with economic difficulties, a persistent pandemic and crippling sanctions, would have preferred to sweep this incident under the carpet, were it just incompetence or an accident. Instead, it has chosen to amplify and prolong the suspicions.
    A similar pause was applied in October when an Iranian tanker, the Sabiti, was apparently hit by missiles after a long, escalatory series of standoffs and explosions against Saudi, Gulf and Western assets in the Gulf.
    Iran was able to diffuse that increase in tension -- which came after an attack on Saudi Arabia's Aramco oil fields that Tehran was accused of but denied -- by letting slide this possible retaliatory move by opponents in the region.