The Iranian Al-Alam television channel broadcast footage on Wednesday of the sailors and an interview with the lone female sailor among the detainees.
The sailor said Iran had been "very, very compassionate" and that she had been well-treated.
The television channel also showed a letter that it said she had been allowed to send to her family in Britain.
Manouchehr Mottaki, Iran's foreign minister, told AFP news agency that the female sailor would be released "within a day or two", following similar reports on the CNN Turk television network.
Style, of the Royal Navy, said London "unambiguously" contests Iran's claims that the eight sailors and seven marines were in Iranian waters.
"The action of the Iranian forces is unjustified and wrong. As such it is a matter of deep concern," he said.
"The British may prefer diplomacy... but they don't like being humiliated"
Surfdog1958, Baton Rouge, US
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Style said Iran's contention that the British sailors were two nautical miles inside Iranian waters was not backed up by GPS co-ordinates.
He said: "It is hard to understand a legitimate reason for this change of co-ordinates."
A foreign office official said Britain will suspend all official visits between it and Iran, as well as halting the issuing of visas to Iranian officials, pending a full resolution to the crisis.
"No government to government business will be transacted on any other issue," the official said, adding that British government support for other bilateral events such as trade missions to Iran would also be suspended.
On Tuesday, a spokesman for Blair said that Britain had not released the details of the sailors' position sooner because Britain didn't "want to escalate" the diplomatic stand-off.
Seized at gunpoint
Britain insists that the seized servicemen were conducting "routine" anti-smuggling operations when they were seized at gunpoint in the Shatt al-Arab waterway in the north of the Gulf on Friday.
Iran says they had illegally intruded into Iranian waters.
The EU has demanded the sailors' release and the US has expressed its "concern and outrage" over the situation.
The German foreign ministry said on Tuesday that it had called in the Iranian ambassador to Berlin and reiterated a demand for the immediate release of the British naval personnel.