The man’s motive was not immediately clear.

“The man suffered burns to some 40 percent of his body and we suspect his respiratory system was also affected. He is about 40-50 years old,” a spokesman for the ambulance service, Marek Niemirski, told Reuters.

Prime Minister Donald Tusk’s ruling center-right Civic Platform (PO) is tipped to win the Oct. 9 election. The campaign has so far been relatively low-key.