Several incendiary devices were set off during the night outside Munich-based technology group Rohde & Schwarz and German drone manufacturer Helsing.Investigators currently believe that two of the devices ignited, while the third apparently did not.A witness called the police at around midnight after incendiary devices were thrown from a moving car at a building site on the street.Officers who arrived at the scene were able to extinguish the fire immediately. No major damage was reported.The suspects, a 38-year-old man and a 28-year-old woman, were then arrested. According to German public broadcaster Bayerischer Rundfunk, both suspects are Bulgarian nationals.Rohde & Schwarz manufactures, among other things, security and communications technology for public authorities and the military. Helsing mainly produces drones for military operations. No further details about the background to the incident are yet known.In our own coverage: you can also watch the latest Euronews exclusive report: