Unidentified foreign forces have launched a night-time raid on a militant base in the south Somali town of Barawe from the sea, reports say.
Senior militants, said variously to be from Somalia’s al-Shabab Islamist group or al-Qaeda, were reportedly targeted.
At least one al-Shabab fighter was killed in the attack, in which a helicopter was also used.
Al-Shabab claimed a deadly attack on a Kenyan shopping centre last month, which left at least 67 people dead.
Militants stormed the Westgate mall in the capital, Nairobi, on 21 September, in an act which caused international outrage.
Both US and French special forces have carried out raids on coastal targets in Somalia in recent years.
There was no immediate comment on Saturday’s alleged attack in Barawe from the Western-backed authorities in Somalia.
‘Westerners in boats’
Reports speak of residents in the militant-controlled town, which is about about 180km (110 miles) south of the capital Mogadishu, being woken by heavy gunfire before dawn.
Commandos rappelled from a helicopter as they tried to storm a house belonging to a senior al-Shabab commander, witnesses told AFP news agency.
“I woke to the sound of the helicopter above the neighbourhood, then a few minutes later, there was fighting, gunfire broke out for about 10-15 minutes,” a local resident said.
“We don’t know what exactly happened, but it was an organised attack targeting the house where some al-Shabab commanders were.” No names have been disclosed.
Local al-Shabab commander Mohamed Abu Suleiman told AFP that the raid had failed.
Sheikh Abdiasis Abu Musab, described as al-Shabab’s spokesman for military operations, told Reuters that “Westerners in boats” had attacked the group’s base at Barawe beach.
One militant was killed, he said, in a report confirmed by Somalia’s Jowhar news website.
Militants rushed to the scene to capture a foreign soldier but were unsuccessful, the military spokesman added.
Residents quoted by Jowhar also said the house targeted was believed to be sheltering senior al-Shabab leaders.
However, an unnamed Somali intelligence official told the Associated Press that the targets of Saturday’s raid had been “high-profile” foreigners.
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.