The Foreign Office has changed its travel advice for Italy after a volcano 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."
Tourists threw themselves into the sea for safety following the eruption, According to Italy's ANSA news agency.
Witness Gianluca Giuffre told the agency people barricaded themselves in houses and sought shelter in the sea after the "very violent explosion followed by a shower of glowing lapilli and lava material".
The volcano, nicknamed "the Lighthouse of the Mediterranean", is described as "one of the most active" on earth which has been "erupting almost continuously" since 1932, according to the geology.com website.
The site described its activity as varying "from mild degassing to lava flows to violent explosive eruptions" and says it is one of the world's most visited volcanoes.
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.