The US military has stepped up its campaign of air raids in Somalia since President Donald Trump took office, saying it has killed more than 800 fighters in two years.
The Islamic State of Iraq and the Levant (ISIL, also known as ISIS) has gathered recruits in Puntland, although experts say the scale of its force is unclear and it remains a small player compared with the al-Qaeda-linked al-Shabab group that once controlled much of Somalia.
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US Africa Command (AFRICOM) said late on Thursday that the latest raid on Wednesday targeted an ISIL-Somalia camp in the Golis Mountains.
"At this time, it is assessed the air strike on May 8 killed 13 terrorists," it said.
In April, AFRICOM had said it killed Abdulhakim Dhuqub, identifying him as ISIL's deputy leader in Somalia.
Last month, AFRICOM also said it has resumed air raids against the al-Shabab group in Somalia after a brief pause that followed a critical report condemning the "shroud of secrecy around civilian deaths" caused by the US military.
The aerial bombardment was believed to be the first since Amnesty International said in a March 18 report that 14 civilians had been killed and seven wounded in the course of five air raids between April 2017 and December 2018, all attributed to the US military.
Initially, AFRICOM denied its operations had resulted in any civilian deaths, but later acknowledged that a woman and a child had been killed in an April 2018 raid.
Somalia has been mired in a civil war and armed rebellion since 1991 when clan warlords overthrew a dictator and then turned on each other.
Al-Shabab was pushed out of the capital Mogadishu in 2011, but retains a strong presence in parts of southern and central Somalia and has often clashed with the ISIL.
