A volcano has erupted on the Sicilian island of Stromboli, killing a hiker and reportedly sending tourists fleeing into the sea.
Images on social media show large clouds of smoke filling the sky with several fires burning visibly through hazy, ash-filled air covering the island just north of the boot of Italy.
Civil protection authorities said a hiker was killed during the eruptions on Wednesday.
Fiona Carter, a British tourist on neighbouring island Panarea, told PA: "There was a loud boom and a huge plume of white and grey smoke rose up from Stromboli. The locals were clearly shocked.
"The cloud became a very big mushroom cloud. Then we saw streams of red-hot lava running towards the small village of Ginostra.
"The cloud continues to spread across the sky and Stromboli has disappeared from view. Highly unusual and huge explosion according to the locals."
Another eyewitness told the Italy's ANSA news agency: "A huge column of dense black smoke is coming out of the crater."
Another said "there was a powerful explosion. We heard a bang, then a column of smoke and lapilli fell onto Ginostra, and flames on the slopes of the volcano."
A social media user said: "Major #eruption on #Stromboli sudden and major, I really hope everyone is ok the whole mountain just blew up a few seconds ago."
The violent explosions triggered a thick ash cloud which rose 2km into the air.
Fires have broken out across the island, fire services and forest rangers said, but no injuries have been reported.
Eyewitnesses in nearby Sicily and the mainland of Italy have posted videos and photographs on social media, showing the ash cloud rising into the air.
The eruption ejected lapilli, red-hot rocks, over the summit area, and residents in the nearby village of Ginostra were reported to have responded in panic.
Large eruptions are rare on the island, on average there are only about one or two a year.
Photos on social media show small pyroclastic flows travelling down the Sciara del Fuoco, according to Volcano Discovery.
The eruption had been "paroxysmal" which happens when high-pressure magma explodes from a shallow, underground reservoir, according to Stefano Branca from Italy’s National Institute of Geophysics and Vulcanology (INGV).
The president of the region of Sicily Nello Musumeci tweeted that action was being taken.
The volcano, nicknamed "the Lighthouse of the Mediterranean", is described as "one of the most active" on earth and has been "erupting almost continuously" since 1932, according to the geology.com website.
The Foreign Office changed its travel advice for Italy, saying: "Local authorities have responded and are monitoring the situation.
"There are no reports of significant impact on populated areas, but localauthorities are assisting those on the island who wish to leave.
"If you're in the area, you should follow the advice of local authorities."
Stromboli's population is around 500 and its economy is based almost entirely on tourism.