Local residents told Shabelle Media Network they saw Kenyan troops open mortar fire on rebel bases at Qoqani, an insurgent stronghold in the Lower Jubba region.
The witnesses said they observed many injured taken to hospitals for treatment, though the number of casualties was not reported.
Meanwhile, gunmen Wednesday shot to death a Somali journalist in Galka'yo. Farhan Jeemis Abdulle was gunned down as he walked to his home after leaving work, a colleague said.
He was the fifth journalist to be killed in Somalia this year, Shabelle said.