The U.S. military says it has carried an airstrike that killed 18 al-Shabab extremists after U.S. and local forces came under attack in southern Somalia.
The U.S. Africa Command says in a statement the airstrike was carried out in self-defence on Friday about 50 kilometres (31 miles) northwest of the port city of Kismayo.
The statement says two other al-Shabab extremists were killed by Somali forces ``with small arms fire during the engagement.''
An AFRICOM spokesman says no U.S. or partner forces were injured. The spokesman says the airstrike was carried out after extremists were ``observed manoeuvring on a combined patrol'' of U.S. and Somali forces.
The U.S. has carried out more than 20 such airstrikes this year against the al-Qaida-linked al-Shabab, the deadliest Islamic extremist group in sub-Saharan Africa