A two-storey building has collapsed after a powerful explosion in Plaka, the old quarter at the foot of the Acropolis in central Athens, early on Friday morning.

The blast struck an old building on Lysikratous Street, at its junction with Vasilissis Amalias Avenue, directly opposite the surviving columns of the Temple of Olympian Zeus. A passer-by suffered minor injuries from flying debris.

Firefighters freed two women trapped in a neighbouring building. One is elderly and the other is aged around 50. Both were taken by the National Centre for Emergency Care (EKAB) to Gennimatas General Hospital for treatment.

The cause has not been officially confirmed, but initial indications point to a natural gas leak. The building that collapsed was reportedly being used as short-term rental accommodation.

Earlier reports of people calling for help had raised fears that some were trapped inside the building itself.

The explosion was heard across much of central Athens. Debris damaged parked cars, and the shock wave shattered windows and damaged shops nearby. The Fire Service said the blast also started a small fire.

The Fire Service’s operations centre was alerted at 7.45am. It deployed 20 firefighters with six vehicles, along with two specialist rescue vehicles from the 1st Special Disaster Response Unit (EMAK). The City of Athens sent heavy machinery to assist.

Athens Deputy Mayor for Urban Planning Paris Charlaftis told state broadcaster ERT that early evidence suggested a gas malfunction or leak during the night. He stressed, however, that firm conclusions could only be drawn once the Fire Service investigation was complete. “What we can say with certainty is that the building is a total write-off,” Charlaftis said, adding that municipal engineers would carry out an inspection.

The adjacent building also suffered extensive damage. A sign at its entrance gives 1880 as its year of construction. “I don’t know whether it is habitable. Given its age and the explosion, it may also be declared unsafe,” Charlaftis said.

The Athens Arson Crime Investigation Unit has been called in to determine the cause.

Witnesses described a strong smell of gas before the explosion.

“Smoke came out and I watched the building collapse in front of me. All the windows shattered,” a woman who works in the area told reporters. “There was an elderly lady inside, but she got up and walked away. The police came and got us out. At first they said it was a car bomb, then they told us it was gas.” Asked whether there had been a strong smell beforehand, she said there had.

Another woman working nearby, who was at the scene at the time, said: “The bang was loud, but we weren’t hurt, we got away. It smelled like gas, and there was smoke. I saw an elderly man at the entrance downstairs who had hit his head. There are three injured. Our flat, one of the flats, has been destroyed.”