Russian saboteurs burned down a Berlin factory to hit weapons supplies to Ukraine. Just one problem — the facility made car parts.

A month later, The Wall Street Journal reports that the fire at the Diehl Metal factory was an arson attempt carried out under Russia’s auspices.

Citing unnamed security officials, the outlet reported on Sunday that a NATO intelligence agency had intercepted communications showing Russia’s involvement and passed it to German authorities.

German outlet Bild also reported on the intercepted messages.

The Journal reported that Russia’s intention was to hit arms supplies to Ukraine. Diehl Metal’s parent company also manufactures the IRIS-T anti-air systems given to Kyiv.

But Diehl Group’s arms manufacturer, Diehl Defence, only has a representative’s office in Berlin, and its factories and major facilities are spread across southern Germany.

Meanwhile, the Diehl Metal factory that burned down instead makes parts “primarily for the automotive and electrical industries,” according to its website.

The Journal reported, citing the unnamed security officials, that Germany hasn’t blamed Russia for the fire because the intercepted messages aren’t admissible in German courts.

Still, the fire at the Diehl Metal factory has added fuel to concerns of Russian sabotage attempts on civilian infrastructure and military installations among Ukraine’s European allies.

Suspected targets in recent months include a warehouse in the UK that was set on fire and US military bases in Germany.

The Financial Times reported Latvian President Edgars Rinkēvičs saying the spate of incidents and attempts was “testing our response” and that NATO was still determining how best to act.

US State Secretary Antony Blinken said on May 31 that the alliance has been tracking sabotage attempts closely.

“I can tell you that in the meeting of foreign ministers today virtually every ally was seized with this intensification of Russia’s hybrid attacks,” he said at a press conference in Prague. “We know what they’re up to, and we will respond both individually and collectively as necessary.”

Diehl and the Russian Foreign Affairs Ministry did not immediately respond to requests for comment sent by Business Insider outside regular business hours.