Details of a UK operation to rebel-held Benghazi in Libya in which eight men - six reportedly SAS - were detained, have been disclosed to the BBC.
The BBC's Jon Leyne said witnesses saw six men in black overalls land in a helicopter near the city on Friday.
They were later seized when it was discovered they were carrying weapons.
State TV has played a tape where a man said to be the UK ambassador tells a rebel spokesman the team went to liaise with rebels on the National Council.
He carries on to say the group wanted to keep an eye on the humanitarian situation in Benghazi.
Defence Secretary Liam Fox said a small diplomatic team was in Benghazi and "they were in touch with them".
The BBC's security correspondent Gordon Corera says the SAS was believed to have been in Libya protecting diplomats rather than on a military mission.
The Sunday Times reported earlier that the unit was trying to put UK diplomats in touch with rebels trying to topple the Gaddafi regime.
In a statement, the MoD said: "We neither confirm nor deny the story and we do not comment on the special forces."
Jon Leyne, who is in Benghazi, said the men went to the compound of an agricultural company where they were challenged by Libyan guards and asked if they had weapons.
"Witnesses said that when the men's bags were checked they were found to contain arms, ammunition, explosives, maps and passports from at least four different nationalities.
"The witnesses said at that point all eight men were arrested and taken to an army base in Benghazi where they are being held by the opposition forces who control this area."
Meanwhile, the British evacuation of EU nationals continues, with the Royal Navy frigate HMS Cumberland setting sail from Benghazi.
In other developments, eyewitnesses and rebels say four towns which Libyan forces loyal to Colonel Gaddafi claim to have retaken actually remain under rebel control.
BBC staff report that Tobruk and Ras Lanuf remain in rebel hands.
Anti-Gaddafi forces still control Misrata and Zawiya, residents and rebels said. But Misrata was reported to be under renewed attack on Sunday.
Officials in Tripoli said pre-dawn gunfire there was celebrating pro-Gaddafi "gains" of the towns.
Separately, a group of Dutch special forces was apparently captured by Col Gaddafi's forces in western Libya while trying to assist Dutch nationals evacuate.
Earlier, the MoD confirmed Scottish troops were on standby to assist with humanitarian and evacuation operations in Libya.
Defence Secretary Liam Fox told the BBC the UK had no plans to use British land forces in Libya.
The Black Watch, 3rd Battalion of the Royal Regiment of Scotland, is on a routine deployment notice of 24 hours at an RAF base in Wiltshire.
Former foreign secretary, David Miliband, told the BBC's Andrew Marr show that Libya was going to have to be a "big squeeze rather than a big bump on Gaddafi".
He said they would need to squeeze his oil money, squeeze him politically and also "make sure people know that they have our support".
Questioned about Col Gaddafi's son Saif giving the Ralph Miliband memorial lecture at the LSE last year, he said it was "horrific".
Set up to honour his academic father's memory, he said it had been "horrific to the whole family, obviously".