* 5.1 magnitude quake shakes Greek capital
* Reports of three people injured, minimal damage
* Some tall buildings evacuated
* Second strong tremor felt 40 minutes later
* Revered Acropolis is intact (Updates wth PM and minister comment, number of injured)
ATHENS, July 19 (Reuters) - A magnitude 5.1 earthquake rattled the Greek capital Athens on Friday, briefly knocking out power and telecommunications in parts of the city and sending people running from buildings in panic.
The European Earthquake Monitoring Centre recorded the quake's epicentre at a point 22 km (14 miles) northwest of the city. Its website quoted a witness as saying the quake was "strong but fortunately not very long", while another compared it to a "strong bounce" lasting about 15 seconds.
The Acropolis, a complex of ancient Greek buildings including the Parthenon located on a rocky hilltop overlooking the capital, was intact, according to the authorities. It is one of the world's most visited historical landmarks.
Reuters correspondents saw people evacuating buildings in the sprawling capital, and hundreds crammed into central Syntagma Square.
Three people including a Belgian tourist were lightly injured by falling debris, health ministry officials said. In the port city of Piraeus, an abandoned structure on a port quay collapsed.
The quake occurred at a depth of 15 km (9.3 miles) in an area affected by earthquakes in the past. Greece, along with Turkey, is among the most tremor-prone regions of Europe.
"The earthquake was close to the surface, which is why it was felt so much," seismologist Manolis Skordilis told Greece's Star TV.
Citizens' Protection Minister Michalis Chrysochoidis said there had been 30 calls asking the fire brigade for help in rescuing people trapped in elevators, while some abandoned buildings were damaged.
He said the sequence of post-quake tremors was normal, which the Athens Geodynamic Institute considered to be a positive sign.
Prime Minister Kyriakos Mitsotakis said the response of state services to the earthquake was satisfactory.
"We have learned to live with earthquakes, this was one more quake," he told reporters after visiting the civil protection coordinating centre in Athens, a metropolis of almost 4 million people.
"The situation is gradually subsiding. The city withstood this and can handle it. There is no cause for concern," said Nikos Hardalias, general secretary for Civil Protection.
Around 40 minutes after the first tremor, residents felt another strong quake, which the EMC rated magnitude 4.4, with an epicentre in the same region at the foot of Mount Parnitha.
In 1999, an earthquake of magnitude 5.9 in the same area killed 143 people. (Reporting by George Georgiopoulos, Renee Maltezou, Lefteris Papadimas, Angeliki Koutantou, Karolina Tagaris and Michele Kambas Editing by Mark Heinrich)
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