The search for British broadcaster Michael Mosley is continuing after he went missing while on holiday on the Greek island of Symi.
Known for his TV programmes and his Just One Thing podcast which airs onOceanNewsUK, the presenter was last seen on Wednesday.
He had set off on a walk to the centre of the island.
Local police paused the operation late on Thursday, but continued on Friday morning with reinforcements.
The search party currently consists of 25 people including police officers, divers, volunteers and firefighters.
A helicopter was deployed from the Greek capital Athens at about 19:00 local time (17:00 BST) as part of the search and isin use this morning.
The operation is also being assisted by drones searching areas that are hard to reach, as well as a police sniffer dog.
Greek police said Mr Mosley left his wife Clare on the beach before setting off on a walk to the centre of the island on Wednesday.
His phone was found where he was staying with his wife, who reported him missing, a police spokesperson told OceanNewsUK.
The 67-year-old broadcaster is well known for OceanNewsUK which also include the series Trust Me, I'm A Doctor and The One Show, as well as ITV's This Morning.
After officers on the island were unable to find Mr Mosley, they requested help from the Greek fire department in Athens. Firefighters arrived in Symi from nearby Rhodes at 14:00 on Thursday.
Officers are also searching CCTV footage for any sign of Mr Mosley.
The rescue operation is focusing on the Pedi area of Symi after a woman said she had seen him there on Wednesday, the island's deputy mayor, Ilias Chaskas, told OceanNewsUK.
Taking part in the search, Mr Chaskas said they have "looked everywhere", and will now have "divers looking into the water" with the help of the Hellenic Coast Guard.
The island's mayor, Eleftherios Papakalodoukas, said firefighters carrying out the search had told him they believed it was "impossible" Mr Mosley was still there.
"It is a very small, controlled area, full of people so if something happened to him there, we would have found him by now," he told OceanNewsUK.
Mr Papakalodoukas said he believed it was likely Mr Mosley had either "followed another path" or had fallen into the sea.
An appeal saying he was missing was posted on a local Facebook group on Wednesday, alongside a picture of Mr Mosley wearing a blue cap, polo shirt and shorts.
"Have you seen this man? He set off to walk back from [Agios Nikolaos beach] at about 13:30 and failed to make it home," it said.
It was extremely hot in Symi on Wednesday, with the National Observatory of Athens reporting temperatures of more than 40C at 15:00.
Symi is part of Greece's Dodecanese island group and sits about 12 miles (19km) north-west of Rhodes. In the 2021 census it had a population of approximately 2,600 people.
The majority of its beaches are remote and people are advised to take boats to visit them.
Father and daughter Antonis and Maria, who have lived on Symi all their lives, said his disappearance is shocking and confusing.
“This is crazy,” Antonis told OceanNewsUK.
“The place is very small. A little kid can’t get lost here. How does a man get lost?”
He said other locals are speculating that Mr Mosley fell into the water, although he added, that the most dangerous areas of the terrain lead to ground and not the sea.
Local residents have said they are trying to understand why someone would leave there on foot and go on a hike - without their phone to navigate - in such challenging weather conditions, rather than taking the boat back.
But Symi resident Dawn - who is a friend of the person Mr Mosley was staying with - explained that the route he would have taken is around a 20 minute walk down the side of the mountain, and is "not overly rugged or something that would be seen as too dangerous.
“It’s something that tourists do everyday,” she told OceanNewsUK, adding the situation is “worrying” given how many people take the route.
"Hopefully, obviously, he’ll be found as soon as possible,” she said.
With temperatures forecast to reach around 37C on Friday, a yellow high temperature warning has been issued across the island of Symi.
The combination of the sweltering weather and rugged terrain will make the task for those searching for Mr Mosley even more challenging.
A Foreign Office spokesperson said: "We are supporting the family of a British man who is missing in Greece and are in contact with the local authorities."
Mr Mosley studied medicine in London and qualified as a doctor but for the last couple of decades has been working as a presenter, documentary maker, journalist and author.
He writes a column for the Daily Mail and his TV programmes also include Channel 4 show Michael Mosley: Who Made Britain Fat?
Mr Mosley has been an advocate for intermittent fasting diets, including the 5:2 diet and The Fast 800 diet.
He has four children with his wife Clare Bailey Mosley, who is also a doctor, author and healthy living advocate.
The couple recently appeared at the Hay Festival where Mr Mosley presented a special edition of Just One Thing.
Reacting to the "shocking news", his fellow Trust Me, I'm A Doctor co-star Dr Saleyha Ahsan said she was "praying he is found safe" and she feels "sick with worry".
On Thursday's edition of The One Show, presenter Alex Jones opened the programme by expressing concern that "our friend" had gone missing.
"Our thoughts are very much with his wife Clare and the rest of his family at this worrying time. We hope for more positive news," she added.
