Polish Prime Minister Donald Tusk said a fire at a defense plant producing components for unmanned systems was deliberately set in an act of sabotage on Wednesday, Sept. 2.According to Polskie Radio, Tusk made the announcement before a Cabinet meeting while discussing recent fires at two industrial facilities.JOIN US ON TELEGRAMFollow our coverage of the war on the @Kyivpost_official.The confirmed case involved a plant operated by Polish defense contractor WB Electronics in Skarżysko-Kamienna, a city in south-central Poland.“In the case of Skarżysko-Kamienna, there is no doubt that it was deliberate arson, an act of sabotage,” Tusk said.The fire broke out early on Monday at the WB Electronics facility. Prosecutors said warehouse facilities were destroyed, causing damage estimated at no less than 15 million zlotys ($4 million).Polish prosecutors opened an investigation into suspected activity on behalf of a foreign intelligence service and a terrorism-related offense. Investigators said the fire had been started using a device containing flammable materials, Euronews reported.WB Electronics is Poland’s largest private defense company which manufactures reconnaissance and attack drones used by Ukraine’s military.Firefighters extinguished the blaze in under two hours, with no injuries reported.Second fire in LublinTusk said investigators had not found evidence that a separate fire at a production and storage facility in Lublin was deliberately started. He added that arson could not be ruled out because of the nature of the company’s work.