US base, EU convoy attacked by Al-Shabaab in Somalia
The militants hit the US base at Baledogle, about 110 kilometres (70 miles) northwest of the capital Mogadishu, with explosives before gunmen opened fire on the compound.
"In the early hours of Monday morning, an elite unit of soldiers... launched a daring raid on the US military base" in Baledogle, al-Shabaab said in a statement.
"After breaching the perimeters of the heavily fortified base, the Mujahideen (holy fighters) stormed the military complex, engaging the crusaders in an intense firefight."
The battle was ongoing, al-Shabaab said.
Baledogle is a major launching site for US drone operations against al-Shaabab, an al-Qaeda-linked group which controls large parts of Somalia, and the Islamic State in Somalia outfit.
"Two heavy explosions occurred, the first one bigger than the other. There was also a heavy exchange of gunfire after the blasts but we don't know about the details," Mohamed Adan, a Somali elder close to the scene of the attack, told AFP by phone.
In a separate incident on Monday, a security official said EU advisers training the Somali National Army were also attacked by a car bomb in Mogadishu.
"There was a car bomb targeting the EU military advisors along the industrial road. A vehicle loaded with explosive was rammed onto one of the convoy vehicles and there are casualties," said Omar Abikar, a Somali security officer.
Italy's vice minister of foreign affairs, Emanuela Del Re, said on Twitter that Italian soldiers had been targeted in the attack.
"Very worried for the explosion at the passage of Italian soldiers #EUTM in Somalia," she said, referring to the European Union Training Mission in Somalia.
SITE Intelligence, which monitors militant activities worldwide, said al-Shabaab had claimed responsibility for both attacks.
The attacks are the latest in a long line of bombing and assaults claimed by al-Shabaab.
The jihadists were driven out of Mogadishu by government forces backed by 20,000 African Union peacekeepers in 2011.
However, the militan group still carries out attacks including suicide bombings against government targets.
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