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Greek officials are searching for a US tourist who went missing after going on a hike alone on the island of Amorgos.

Local officials say Albert Calibet, 59, vanished on Tuesday afternoon. His friend reported him missing when he did not return from his hike.

Several agencies are participating in the search for Mr Calibet, including volunteers from the coastguard and teams from the neighbouring islands of Paros and Naxos, according to Greek public broadcaster .

His disappearance comes days after the British television presenter Michael Mosley went missing on the Greek island of Symi, where his body was found four days later.

The 91�ȱ� has contacted the US state department for comment about the search for Mr Calibet.

Officials are searching both land and water in an area covering almost a quarter of Amorgos, the island's Mayor Eleftherios Karaiskos told ERT.

They have been using a drone to search the northern part of the island and are also attempting to trace Mr Calibet's two mobile phones. Calls to Mr Calibet - who the mayor said had visited the island before - have gone unanswered.

"We’re almost on three days here," his brother Oliver Calibet told Fox 11 TV in Los Angeles. "There’s no water… I’m very distraught."

Oliver Calibet and the girlfriend of Mr Calibet are on their way to Greece to help the search effort, .

The island's mayor said the hike on which Mr Calibet had embarked was busy and not particularly challenging, which suggested that the American could have deviated from his planned route.

Mr Calibet, described as a retired police officer from Los Angeles County, started a hike on Tuesday morning in the village of Aegiali, according to local news outlets.

A few minutes later he is thought to have sent a text message with a picture of the sign showing the route he was taking to Katapola, an estimated four hours on foot.

About two hours later, a local woman said she spoke to the missing tourist after he bought drinks from a nearby store. Sofia Liviaki told Mega TV that Mr Calibet had drunk a soft drink, showed her his planned route and took a bottle of water with him for the remainder of his journey.

Mr Calibet's disappearance has shocked the local community on Amorgos, where he has been a regular visitor for a number of years. While the path he chose is well travelled and not difficult, the island has been experiencing a heatwave with temperatures currently as high as 35C (95F).

"Temperatures are very high, like all of Greece during the heatwave," the island's deputy mayor for tourism, Popi Despotidi, told Greek media. "We're guessing he felt dizzy... and collapsed somewhere. It's odd because he's not someone who was walking this route for the first time."

"Our hope is that we can bring him home safely," Los Angeles County Sheriff Robert Luna told . "We are actively collaborating with multiple agencies abroad to provide assistance in the search for Deputy Calibet and will use every resource we have available to bring him back to those who love him."

The search for the missing man comes just days after officials spent days scouring another Greek island, Symi, for Dr Mosley, a famous British TV doctor who vanished after setting out on a walk from a beach.

His body was found in a rocky area, and investigators concluded that he died of natural causes the day he went missing.

A second American tourist, a 55-year-old, has also gone missing in Greece, on the island of Mathraki, north west of Corfu, according to local media.

And a 74-year-old Dutch tourist disappeared on Sunday on the island of Samos.