An official with the AU force said its armed operations against al-Shabaab safe havens had resumed, targeting the group's camps and senior commanders, Voice of America reported Thursday.
The Kenyan Defense Ministry said its forces within the African Union mission conducted the attack, describing it as an airstrike that "completely destroyed" the training camp.
The ministry said more than 300 al-Shabaab recruits were at the camp when the attack occurred and many of them are believed to have been killed, VOA said.
The ministry says some of the al-Shabaab fighters who attacked a Nairobi mall in September were trained at the camp in the Dinsoor region. That assault at the Westgate shopping mall left at least 67 people dead, not including the attackers.
On Monday, a suspected U.S. drone strike in southern Somalia killed key al-Shabaab operative Ibrahim Ali Abdi, who orchestrated the group's suicide missions.
Al-Shabaab wants to turn Somalia into a strict Islamist state. It claimed responsibility for the Westgate mall attack, saying it was retaliation for Kenya's military intervention in Somalia.