"Bashir Mohamed Mahamoud was a senior operational leader responsible for exporting terror in Somalia as well as attacks into Kenya," said Africom director of public affairs Colonel Christopher Karns.

"He has been a senior al-Shabaab member for more than a decade."

Bashir was killed in a February 22 airstrike, said Karns, describing him as an "individual (who) had a role in planning and directing terrorist operations in Somalia and on the Kenya border region".

Bashir also was suspected of having had a role in a January attack on a US-Kenyan military base in southeastern Kenya in which three Americans were killed, he added.

General Roger Cloutier, commander of US land forces in Africa, recently declared al-Shabaab to be "one of the biggest threats on the continent".

Some analysts have questioned the effectiveness of the US campaign in Africa.

Amnesty International said in a 2019 report that US air strikes sometimes hit civilians as well as Shebab fighters, killing farmers, workers and children.

The US military has generally denied the charge, though it did admit responsibility for civilian casualties in one attack that killed a woman and a child near the central town of El Buur in April 2018.

Colonel Karns described al-Shabaab as "the largest and most kinetically active al-Qaeda network in the world".

"What we are doing in Somalia, as part of an international effort, is meaningful basic security insurance for Africa and the longer term security of America, the continent, and our international partners," he added.