He said that 30 Shabaab militants had been killed, while the Islamists claimed in a statement to have killed 59 Ugandan soldiers.
Underscoring al-Shabaab's threat, the militants carried a coordinated attack on three African Union Mission in Somalia (AMISOM) bases Sunday in the Lower Shabelle region, an al-Shabaab stronghold near the Somali capital of Mogadishu. "Our fighters also attacked five other bases", Mus'ab said.
The gunmen on Sunday detonated at least two cars at the military camp in the town of Bulo Marer, before engaging soldiers from African Union Mission in Somalia (AMISOM). Farah Osman of the Somali Army, who is stationed near the base.
Deputy-Governor of the Lower Shabelle region, where the AU base is situated, said the militants then went on to attack the nearby villages in the area on foot.
The Ugandan military, meanwhile, has only confirmed the deaths of four soldiers.
However, Brig Karemire rebutted: "Do not fall into the propaganda of al-Shabaab".
The U.S. has carried out more than a dozen drone strikes against al-Shabab since a year ago, after the Trump administration approved expanded military efforts against the extremist group.
Al-Shabab, which is often referred to as "the deadliest" Islamist extremist group in Africa, is fighting to impose its hardline interpretation of Islamic law across Somalia.
The group launches regular attacks on government, military and civilian targets.
The militants controlled Mogadishu between 2007 and 2011, when they were driven out of the capital with help from AU troops.
This article has been adapted from its original source.