A 3.6-magnitude earthquake rocked the region near the southern Italian city of Naples in the early hours of the morning on Thursday, the National Institute of Geophysics and Volcanology (INGV) reported.
The institute said the quake occurred at 4:17 am (0217 GMT) in the Phlegraean Fields, a so-called supervolcano.
Local authorities there had reported minor earthquakes almost 24 hours earlier.
Italian media said the tremor was also clearly felt in Naples, particularly on higher floors of buildings and in districts of the city that border the Phlegraean Fields area to the west.
There were initially no reports of injuries or major damage.
The Phlegraean Fields, a volcanically active area near Naples, have experienced persistent seismic activity, with frequent small earthquakes and occasional stronger tremors linked to movements beneath the ground.
The area is part of Europe's largest active supervolcano system.
Unlike conventional volcanoes, supervolcanoes are characterized by vast magma reservoirs capable of producing exceptionally powerful eruptions.
Scientists stress there are currently no indications of an imminent eruption.
About 3 million people live in Naples and the surrounding area. The city lies at the foot of Mount Vesuvius, which has no connection to the Phlegraean Fields.
