* Al Shabaab says one fighter killed in strike
* Foreign forces landed on beach under cover of night
* Residents woken by noise of heavy gunfire and shelling
Somali Islamist militants said on Saturday "Western" forces attacked a house in one of its coastal bases in the town of Barawe under the cover of dark, killing one rebel fighter.
Foreign forces landed on the beach at Barawe, about 180 km (110 miles) south of Mogadishu, and launched an assault that drew gunfire from rebel fighters, Sheikh Abdiasis Abu Musab, spokesman for al Shabaab's military operations, told Reuters.
It was not immediately clear why the Barawe base had been targeted specifically, nor whether the assault was related to the attack on a Kenyan mall two weeks ago, which the al Qaeda-linked group said it carried out and which killed at least 67.
Western navies patrol the sea off Somalia - mired in conflict for more than two decades - and have in the past launched strikes on land from warships.
No foreign military units typically involved in such operations in Somalia have said they were involved in the strike. One Western official in the region declined to comment.
Kenyan forces stationed in the southern parts of Somalia were unavailable for comment.
"Westerners in boats attacked our base at Barawe beach and one was martyred from our side," Musab said.
"No planes or helicopters took part in the fight. The attackers left weapons, medicine and stains of blood, we chased them," he said.
Many residents said they were woken by the noise of heavy gunfire late on Friday night.
"We were awoken by heavy gunfire last night, we thought an al Shabaab base at the beach was captured," Sumira Nur, a mother of four told Reuters from Barawe on Saturday.
"We also heard sounds of shells but we do not know where they landed. We don't have any other information," she said.
Although the United States does not report its activities in Somalia, it has used drones in recent years to kill Somali and foreign al Shabaab fighters.
In January, the French military used helicopters to attack an al Shabaab base in a southern Somalia village to rescue a French hostage. Two French commandos were killed and the insurgents later claimed they had killed the agent.
Western nations are worried that Somalia will sink back into chaos and provide a launchpad for Islamist militancy despite a fragile recovery after two decades of war.
Al Shabaab were driven out of Mogadishu in late 2011 and are struggling to hold on to territory elsewhere in the face of attacks by Kenyan, Ethiopian and African Union forces trying to prevent Islamist militancy spreading out from Somalia. Al Shabaab wants to impose its strict version of sharia, or Islamic law, across the Horn of Africa state.
Last year, the Wall Street Journal reported that the Pentagon was seeking to send drones to Kenya as part of a $40 million-plus military aid package to help four African countries fighting al Qaeda and al Shabaab militants.