The UK Foreign Office says is it "actively investigating" reports that Iran has released five British yachtsmen who have been held for a week.
The crew members, who may have strayed inadvertently into Iranian waters, have been described as a close-knit group, but who are they?
OLIVER YOUNG, 21
Oliver Young's mother said sailing was his passion
The professional yachtsman from Saltash, Cornwall, has been described as "fanatical" about the sport by his father David.
One of four brothers, he has always had an interest in sailing, according to his mother Susan, and after leaving school completed courses before turning professional.
Mr Young said his son had a great deal of experience and he was certain Oliver would "cope with this very well".
But he also told the Plymouth Herald he was worried about the diplomatic stresses and international pressures, and hoped the crew would not be used as a "bargaining chip".
He said: "He's travelled a fair bit. He's got quite a bit of experience under his belt. They'll be coping with it fine out there. We understand they are being well looked after.
Oliver Young's father says his son is 'in good spirits'
"We're confident this will be resolved very quickly. We're all concerned and the sooner they are released the better. It is dragging along longer than we thought it would do."
Oliver's parents had a quick conversation with their son on Monday in which he confirmed he and the other crew members were being well looked after.
Mrs Young said he was a very strong person who would be "absolutely fine" and that she was not worried about their morale.
"As a mother I do feel worried but who wouldn't be? We are just hopeful that it will all come to an end very soon," she said.
LUKE PORTER, 21
Luke Porter's parents spoke to him on Monday, they said
The professional sailor from Weston-super-Mare is "used to dealing with adversity", according to his father Charles.
He described his son as a "very strong character" and "very resilient".
The 21-year-old, who has a twin sister, had been in Bahrain for about two months when the Volvo 60 yacht was stopped almost a week ago.
Mr Porter said he and his wife Beverly were "holding things together" as a family and added they had not spoken to their son since Monday who was "as good as can be expected".
"I got the feeling that the telephone conversation was being fairly well monitored and perhaps there was a guard there or someone that was giving him instructions as to what he could and what he couldn't answer.
"But he sounded, not exactly upbeat, but he sounded in control of his own personal situation."
His mother, Beverly, added that his experience as a yachtsman would help him cope.
"He's with two certainly very close friends that he's sailed with for a number of years now. They get on very well. So certainly the scenario that they're in isn't an unusual one for them.
"They're used to spending a lot of time together on their own, away from family and friends, that's the nature of yachting."
She also said her son did not have an "evil bone in his body" and stressed if the vessel had drifted into Iranian waters it would have been an innocent mistake.
David Bloomer is said to work as a sports broadcaster in Bahrain
Mr Bloomer was travelling on a British passport when he was detained by the Iranian navy but has dual British and Irish nationality.
The Bahrain-based radio presenter is in his 60s and from Malahide, an affluent suburban town near the city of Dublin.
Mr Bloomer and the other crew members were sailing from Bahrain to Dubai in preparation for a forthcoming race in which the presenter was due to broadcast progress updates.
Graham Smith, who sailed regularly with Mr Bloomer before he emigrated in the 1980s, believes he is physically and mentally fit enough to get through what he branded a strange scenario.
"I have absolutely no qualms that he will be extremely well able to cope with a situation like that," he said.
"He's a good communicator - he works as a DJ and radio presenter on Radio Bahrain, and has been around various parts of the world covering various events, sporting events particularly, on their behalf over the years.
"In terms of being able to communicate and talk I see no difficulty with him whatsoever, and I would take him to be a mentally tough guy."
Tour operator Ali Mushaima said Mr Bloomer was a fully qualified off-road racing driver who had lived in Bahrain since the mid-1980s and hosted a Friday morning radio sport show.
He said: "He is a friend of mine and we wish him the best of luck in coming back. He is a very nice person."
OLIVER SMITH, 31
Oliver Smith is the Kingdom of Bahrain's skipper
The yacht's skipper, from Southampton, has been described as "very calm" and "sensible" by Hannah White, an up-and-coming yachtswoman.
Ms White, who worked with him in the past for Team Pindar in the Vendee Globe yachting race, said: "I am sure he will be dealing with the situation as best as he can."
Mr Smith works as an engineer, having completed a degree in ocean science and marine navigation at the University of Plymouth where he sailed with the men's first team.
Later, he spent six months skippering a 50ft survey yacht and doing delivery work in South America and the Caribbean.
He was part of a team which came third in the Racing Division of the Atlantic Rally for Cruisers, and in 2003 went on to work for Pure Sailing as the boat captain and skipper for a Volvo 60 racing boat.
Mr Smith has been involved in Team Pindar for many years with more than 100,000 sailing miles under his keel, according to Andrew Pindar, chairman of Sail Bahrain and owner of the seized boat.
SAM USHER, 26
Sam Usher, seen here on the left in the green t-shirt, is a father of two
The businessman from Scarborough in North Yorkshire owns Wykeham Watersports, a sailing academy on the Dawnay Estate in north east York.
He runs the five-year-old centre with his fiancée Nicola Drayton, with whom he has two children.
Ms Drayton said: "It's difficult but you just get on, you have no choice."
On 19 November, Mr Usher posted a message on social networking site Facebook which read: "Hi Lads, see you in a few days for the event. hope all has been going ok!"
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