Al-Shabab militant base 'attacked' on coast of Somalia
Islamist fighters in southern Somalia say Western forces have launched a night-time raid on one of their bases.
The militant group al-Shabab told the BBC "white soldiers" had arrived by boat at the port of Barawe and rebels had repulsed them, losing a fighter.
No-one has admitted the attack. US and French special forces have carried out raids in Somalia in recent years.
It is not clear whether it is linked to last month's attack in neighbouring Kenya, which al-Shabab has claimed.
At least 67 people were killed after militants stormed the Westgate shopping centre in the capital, Nairobi, on 21 September.
Residents in Barawe, which is controlled by militants, say they were woken up by heavy fighting before dawn on Saturday.
"Gunfire broke out for about 10-15 minutes," an eyewitness told AFP news agency.
It is not clear who the target of the raid was.
Several residents are quoted as saying the soldiers tried to storm a house sheltering senior al-Shabab leaders.
However, an unnamed Somali intelligence official told the Associated Press news agency that the targets had been "high-profile" foreigners.
Local al-Shabab commander Mohamed Abu Suleiman said the raid had failed and the group remained in control of Barawe.
Later, Reuters carried a statement by Sheikh Abdiasis Abu Musab, al-Shabab's military operations spokesman, which said that British and Turkish special forces were involved.
He said the commander of the British force was killed, and four SAS and a Turkish soldier were wounded.
However, the UK's Ministry of Defence said there was "no British involvement", while a Turkish foreign ministry official told Reuters that Turkish special forces had also not taken any part.
Western navies tasked with fighting piracy patrol the seas off Somalia, which has been beset by conflict for more than two decades.
In 2009, US Navy commandos attacked and killed an al-Qaeda leader, Kenyan-born Saleh Ali Saleh Nabhan, in a daylight raid on Barawe.
Washington has also used drones in Somalia to support the government and African Union forces in their battle against al-Shabab.
France carried out an unsuccessful raid to free a French intelligence agent in January. Two French commandos were killed and al-Shabab later reported that it had killed the agent.