ATHENS, Greece -- A powerful blast shook the Greek capital’s tourist district of Plaka, near the ancient Acropolis, on Friday morning, causing a building to collapse and injuring at least two people who were rescued from an adjacent building, authorities said. The cause of the explosion wasn’t immediately clear, but local media said that a gas leak was suspected. Rescue crews with a sniffer dog were searching the rubble for potentially missing people, the fire department said. Residents said that two people lived in one of the building’s apartments, and there were media reports that three tourists may have been staying in a short-term rental apartment also in the building. The fire department said that the explosion occurred in an old two-storey building in the Plaka district, the historic part of Athens that lies at the foot of the Acropolis hill, Greece’s most visited ancient monument. The building collapsed, while neighbouring buildings were also damaged. Firefighters rescued two women from an adjacent building, with police saying both were being transported to a hospital. Local media and a resident said that a passerby was also slightly injured by the blast. Video footage from the scene showed rubble strewn across the street, with parked cars smashed by falling debris. Police cordoned off the area as rescue crews and the sniffer dog moved slowly over the rubble. The fire department said that the search and rescue operation was still ongoing several hours after the explosion. “An elderly couple lived upstairs, on the second floor,” resident Andreas Martzaklis said, adding that he didn’t know whether they had been inside at the time of the explosion or managed to get out. He said that one apartment in the building that collapsed had been operating as a short-term rental apartment, while the others were privately owned. “Who got out of the building that is destroyed, we don’t know anything,” said Martzaklis, who lives in a nearby building and heard the blast while he was drinking his morning coffee. The people rescued by the fire department from the adjacent building were all tourists, Martzaklis said. The pastor of a nearby church said that this Sunday’s service would be held outdoors because of damage to the church from the explosion. “Of course we went in. It was heartbreaking. From the bottom to the top, there is no window that has not been broken,” said Giotis Kantartzis, pastor of the First Greek Evangelical Church in Athens. By Lefteris Pitarakis and Elena Becatoros, The Associated Press