The attack on Monday morning took place at the Sarira Forward Operating Base in the Lower Jubba region of southern Somalia near the border with Kenya, Associated Press reported.
It added that Al-Shabab through its media confirmed it had carried out the attack.
The Kenyan military official said, “As we near the festivities, we need to be very vigilant of our surroundings. The terror threat is still rife and all measures should be taken to tame any plan.”
“It is at this time the militants know we might let our guard down as we watch” the World Cup, the official said.
Kenyan authorities also are urging vigilance after the start of the soccer World Cup in Qatar. In 2010, at least 76 people were killed when al-Shabab targeted a rugby club and a restaurant in the Ugandan capital, Kampala, where customers were watching the World Cup final on giant screens.
Kenyan troops, who are deployed to Somalia under the banner of the African Union, are active along the border with Somalia. Peacekeepers from Burundi and Uganda are based in or near the Somali capital of Mogadishu, the seat of the federal government, the source added.
AMK/PR