(Updates with details)
PARMA, Italy, Dec 23 An earthquake of 5.1 magnitude struck northern Italy on Tuesday near the city of Parma, but no damage or injuries were reported, Italy's civil protection agency said.
The earthquake was unusually strong for northern Italy and was felt from the financial capital Milan to Florence to Trieste.
Startled Italians jammed telephone lines after the quake and train service was briefly interrupted on some lines, local media reported.
"There is some anguish, a lot of fear ... in the town hall itself there was a lot of panic," said Alberto Pazzoni, mayor of Traversetolo, a town just outside Parma and very near the quake's epicentre.
"But the information we have got from the police and local health services is very comforting. There have been no calls to emergency services," he said.
Earthquakes can be particularly dangerous in parts of Italy where centuries-old buildings are left in disrepair. In 2002, an earthquake measuring 5.4 flattened a school in southern Molise region, killing 27 children and a teacher.
Enzo Boschi, head of the National Institute of Geophysics, said this quake appeared to be "nothing catastrophic". Still, he warned there could be more quakes of smaller magnitude in the coming hours.
"The area (near the quake's epicentre) is well constructed, so there shouldn't be serious problems," Boschi told Sky Italia television.
The U.S. Geological Survey, which estimated the earthquake's magnitude at a slightly higher 5.3, said it struck at a depth of 28.9 km (18 miles). It ranks quakes in this range as moderate.
Italy's civil protection agency said its struck at a depth of 26 km.
"A lot of people were afraid," said Giordano Bricoli, mayor of the small town of Neviano degli Arduini, also near the epicentre.
He estimated the quake lasted about 20 seconds and said officials were verifying whether any buildings had collapsed.
(Reporting by Phil Stewart and Gavin Jones; Editing by Michael Roddy)