German police are investigating a suspected politically motivated arson attack at a construction site outside the Munich headquarters of defence technology company Rohde & Schwarz, authorities said on Thursday.

A Bavarian police spokesperson confirmed an investigation into suspected arson but said there was currently no evidence that the attack had been directed specifically at Rohde & Schwarz.

The police spokesperson said a 28-year-old woman and a 38-year-old man, both Bulgarian nationals, were arrested in connection with the incident.

The fire caused no significant damage and was quickly extinguished. No one was injured, police said.

Rohde & Schwarz confirmed that an incident had occurred at a construction site near its headquarters.

German authorities are on high alert for attacks on infrastructure after the government this week said Russia was behind an attempted drone attack on a Ukrainian cargo plane at Leipzig/Halle airport last month.

German Interior Minister Alexander Dobrindt has said that foreign powers, particularly Russia, could be using left-wing extremist groups as proxies for sabotage, warning that some of them increasingly echo Russian narratives on the Ukraine war.