ATHENS (AP) — Greek police have closed off a busy road south of Athens after a man was seriously wounded in a car explosion that started a parking lot fire.

Four cars were burned following the blast Friday morning in the upscale Glyfada area south of Athens. Police were investigating reports from witnesses who said the blast occurred after the man started the ignition, according to the Associated Press.

Residues of an explosive device have been found at the scene by investigating officers and member of the police bomb squad, Athens Macedonian New Agency says citing police sources. According to the same sources, the luxury car with Australian licence plates belongs to a 56-year-old foreign national and is thought to have exploded when the injured man got into the driver’s seat and started the engine.

The injured man was picked up by an ambulance and rushed to Voula’s Asklipio hospital, where he was admitted for treatment. Twelve fire men and four fire engines responded to the incident, quickly placing the blaze under control, while Vouliagmenis Avenue remains closed in both directions.