* Quake of 5.7 magnitude - U.S. Geological Survey
* No injuries or damage reported (Adds Athens Geodynamic Institute data)
ATHENS, Aug 29 (Reuters) - A strong earthquake shook southern Greece on Friday and was felt as far as Athens but there were no immediate reports of casualties or serious damage.
The quake measured 5.7 in magnitude, according to the U.S. Geological Survey and struck at sea 80 miles south of the Greek capital. It was 70 miles deep.
No tsunami warning was issued.
The Athens Geodynamic Institute also put the quake, which occurred at 0645 local time (0345 GMT), at 5.7 magnitude and said it was undersea. It was followed by a weaker tremor.
Greece is prone to earthquakes. Most cause no serious damage, but a 5.9 magnitude quake near Athens in 1999 killed 143 people. (Reporting by Angeliki Koutantou and Renee Maltezou; Editing by Anupama Dwivedi)