It was the second operation against al-Shabab carried out under the new authorities granted by President Trump in late March, a U.S. official said.
The operation occurred at 7:30 a.m. ET, a spokesman for U.S. Africa Command (AFRICOM) told ABC News in a statement.
"We are currently assessing the results of the operation, and will provide additional information as appropriate," AFRICOM spokesman Patrick Barnes said. "U.S. forces remain committed to supporting the Federal Government of Somalia, the Somali National Army and our AMISOM [African Union] partners in defeating al-Shabab and establishing a safe and secure environment in Somalia."
The Pentagon has not commented on who was targeted by the airstrike operation, but local media have identified the target as Ibrahim Haji Daud, a senior al-Shabab commander and the leader of the group's intelligence unit.
Last month the U.S. carried out its first offensive strike against al-Shabab under the new authorities.
Those authorities temporarily designated portions of Somalia south and west of Mogadishu to be an active area of hostilities, which means the U.S. could conduct offensive airstrikes. Until that authority was granted, the U.S. could only conduct strikes in self-defense in support of Somali troops and their U.S. advisers.
AFRICOM's Gen. Thomas Waldhauser told Pentagon reporters in March that he had sought greater authority.
"It's very important and very helpful for us to have little more flexibility, a little bit more timeliness, in terms of decision-making process,” he said.
The U.S. has about 50 service members in Somalia, advising and assisting members of the Somali military in its fight against al-Shabab.
In May, a U.S. Navy SEAL was killed during an operation against the terrorist group 40 forty miles west of Mogadishu.
ABC News' Luis Martinez contributed to this report.