ATHENS – After an explosion rocked a whole building in the Greek capital’s downtown, a 78-year-old man who was the only resident there while it was being renovated was found seriously injured, police discovered an old rifle, replica guns, an airgun and 1,000 rounds of ammunition.

The cause was said to be a gas leak in the building near the ancient Temple of Olympian Zeus on the major thoroughfare Syngrou Avenue, several blocks from the Parliament, said Kathimerini in a report on the findings.

Two others received treatment for smoke inhalation, in a report on the findings, the mah taken to a nearby hospital for emergency treatment of extensive burns on his limbs.

The massive explosion seriously damaged an office building while shattering nearby storefronts in a busy part of the downtown and was heard through several neighborhoods, happening just after dawn.

Firefighters used aerial ladders to look for anyone possibly trapped inside the damaged buildings and also went into damaged nearby stores to rescue several people from the rubble, the Associated Press said.