"This precision air strike was the largest air strike against Al-Shabaab since November 21, 2017," when air-dropped US munitions targeted one of the group's training camps, killing about 100 extremists, US Africa Command said in a statement on Tuesday.
The strike took place Friday in the Harardhere area along the central coast of the Horn of Africa country, where US forces train Somali troops and also partner with the United Nations-backed African Union Mission in Somalia (AMISOM).
The surge in activity came after President Donald Trump last year loosened constraints on the US military in Somalia, allowing commanders to take action against suspected militants when they judge it is needed, without seeking specific White House approval.
"Air strikes reduce Al-Shabaab's ability to plot future attacks, disrupt its leadership networks, and degrade its freedom of maneuver within the region," Africa Command said in a statement.
"The group uses portions of southern and central Somalia to plot and direct terror attacks, steal humanitarian aid, extort the local populace to fund its operations and shelter radical terrorists." Friday's air strike came a day before suicide bombers killed at least 16 people at a restaurant and coffee shop in the southwestern city of Baidoa.
Last month, Africa Command said American and allied forces had come under attack in Somalia, triggering an air strike in self-defense that killed 18 Shabaab extremists in the country's south.
More than 500 American personnel are partnered with Somali forces and AMISOM, which aims to counter the threat from Al-Shabaab jihadists.
Shabaab fighters were pushed out of Somalia's capital in 2011, and subsequently from other towns and cities, by AMISOM troops.
But the Islamists still hold sway in large parts of the countryside.
They launch regular gun and bomb attacks on government, military and civilian targets in Mogadishu as well as ambushes on military convoys and outposts.