The US military says it has killed eight members of the al-Shabaab extremist group with an airstrike south of Somalia's capital.The US Africa Command statement says the airstrike occurred on Saturday near Gandarshe, a coastal community. The statement says no civilians were involved.The US military has carried out at least 40 airstrikes this year against the al-Qaeda-linked al-Shabaab, Africa's most active Islamic extremist group. It controls parts of rural southern and central Somalia and continues to stage deadly attacks in the capital, Mogadishu, and other cities.The US airstrikes have picked up dramatically since President Donald Trump took office and approved expanded military operations in the Horn of Africa nation. Airstrikes also target a small presence of fighters linked to the Islamic State group.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.