(Adds official comment, details, background) ROME, Oct 26 (Reuters) - An earthquake measuring 5.7 on the Richter scale rocked southern Italy on Thursday, sending people running into the streets but causing no known casualties, officials said. The National Geophysics Institute said the quake was centred deep in the Mediterranean Sea. It was felt in the southern regions of Puglia, Calabria and Basilicata as well as in Messina, Palermo and other cities on the island of Sicily. The Civil Protection department in Rome said there were no reports of damage or injuries from the quake, which struck at 4:28 p.m (1428 GMT). "The quake was strong and people ran into the streets," a Civil Protection spokesman said. Officials added, however, that any damage would be limited because the epicentre of the quake was very deep -- more than 200 km (120 miles) -- below the sea. "This was very strong but it was also very deep so I don't expect too many problems," said Enzo Boschi, president of the National Geophysics Institute. The last major earthquake to hit southern Italy was in 1980 when some 3,000 people died. A quake near Messina, Sicily, in 1908 killed between 70,000 and 100,000 people. Both registered about 7.2 on the Richter scale.
