American Marconi Wireless News - Six missing after building blast in historic Athens district

The blast on a small street shook the area, which is normally busy with hundreds of foreign visitors.

The police said they were looking for six people missing after the explosion.

The fire service had earlier said they included two elderly people who lived in the building's top floor, and three tourists believed to have rented the apartment below.

Police revised the number of tourists upwards to four.

"A search and rescue operation with a dog is underway to find anyone who may be trapped," a fire department spokeswoman told AFP earlier.

Rescue teams were using excavators to clear debris and thermal cameras to try to locate anyone trapped there, footage from the public television channel ERT showed.

ERT said investigators believe the explosion, which happene at around 7:30 am (0430 GMT), before the collapse of the building, was caused by a gas leak.

According to information provided to the rescue teams and reported by the newspaper Kathimerini, the second floor of the building was occupied by an elderly couple and the first floor by three American tourists, in a short-term rental.

The family of tourists were supposed to leave the rented accommodation and check out around 11:00 am but did not do so, Kathimerini said, adding that the bag of a woman staying in this rented apartment had been found in the rubble.

Earlier, two women were rescued from an adjacent building and taken to hospital. Another person was slightly injured by debris.

Neighbouring buildings and vehicles parked nearby were damaged.

The owner of the ground floor apartment, Mathaios Artavanis, interviewed by Kathimerini, said he had tried to contact "the elderly couple, around 70 years old, since the morning" without success.

Athens city planning services were mobilised to check the stability of nearby buildings, Mayor Haris Doukas told a local radio station.

The historic Plaka district, where the building is located, is one of the most touristy areas of Athens.

It is near Hadrian's Arch, one of the main monuments from the Roman period in the Greek capital, where the tourist season continues to be in full swing.

P.Martin--AMWN