The U.S. has carried out 24 such strikes this year, more than half the number in all of 2018. Several have had death tolls in the double digits, including one in mid-January that killed 52 fighters and one in late January that killed 24.
A U.S. Africa Command statement said the attack occurred Thursday in the Hiran region, where the earlier ones took place. When asked why recent strikes have been deadlier, a spokeswoman said Somali and "partner forces continue to make incursions into territory formerly controlled by al-Shabab," giving them chances to collect more intelligence and develop targets.
The new airstrike was announced shortly after Somali authorities said a deadly overnight siege by al-Shabab had ended in the capital, Mogadishu, with all attackers killed. At least 24 people were killed with more than 50 others wounded, many of them critically.
The attack, which began with a pair of car bombs on Thursday night as Somalis relaxed in a popular neighborhood of restaurants and bars, was one of the most serious in months and was quickly claimed by the al-Qaida-linked al-Shabab.
While the U.S. statement said the airstrikes are meant to degrade al-Shabab's ability to coordinate attacks against the Somali people, the carnage showed that Africa's deadliest Islamic extremist group still has the ability to strike in the heart of the capital.
The U.S. has dramatically increased airstrikes against al-Shabab since President Donald Trump took office. Authorities and experts acknowledge that it will take more than airstrikes to defeat the extremist group, which holds large parts of rural central and southern Somalia.
The group, which claimed the deadly attack on a luxury hotel complex in the capital of neighboring Kenya last month, was also behind the deadliest attack in Somalia's history, a massive truck bombing that killed well over 500 people in Mogadishu in October 2017.
The U.S. military is one of several security actors in Somalia, along with a multinational African Union mission and troops from Kenya and Ethiopia. The United States says it acts in coordination with Somalia's government, whose military is expected to take over primary responsibility for the country's security over the next few years.
The African Union mission has begun a step-by-step withdrawal of forces — the withdrawal of 1,000 Burundian soldiers has begun — but some in the U.S. military and elsewhere warn that Somali forces are not yet prepared.
A United Nations panel of experts monitoring sanctions on Somalia has described the country's troops as largely poorly equipped and underpaid, conditions that cause some personnel to sell their weapons or uniforms for a little cash.
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