Kenyan Defence Forces (KDF) have killed 73 Al Shabaab militants in an attack at a remote region of Fafadun in Somalia, a military source said on Thursday.
"There was an attack in Somalia at a place called Fafadun. Seventy three Al Shabaab were killed and there are two KDF casualties," the source said.
Three other KDF soldiers were wounded in Thursday afternoon's attack.
The KDF headquarters in Nairobi referred our queries to AMISOM which is the umbrella body for all the troops fighting Al Shabaab in Somalia.
The wounded soldiers were expected in Nairobi later on Thursday after being airlifted from the battleground.
"It was a very violent confrontation because the Al Shabaab militants were heavily armed and ready for war. Forty AK-47 rifles were seized from the slain militants," a source told Capital FM News from Somalia.
The KDF soldiers who are part of the AMISOM force are preparing for a major assault in the coming days when they will liberate Kismayu, a key stronghold for the militant group.
On Tuesday, the United Nations warned of an impending assault on the southern Somali port of Kismayu, the largest remaining stronghold of the country's Al-Qaeda linked Al Shabaab insurgents.
"Fighting for control of the town appears imminent," said Mark Bowden, the top UN humanitarian aid official for the war-torn nation, noting reports of recent naval artillery bombardment as well as air strikes.
African Union troops, Ethiopian forces and various Somali militia forces have wrested a string of towns from the hardline Al Shabaab, with the capture of Kismayu - a crucial revenue source for the fighters - seen as a key target.
Last week, Al Shabaab officials and residents said three civilians were killed by missile strikes on the port, reportedly by a naval barrage from an unidentified ship.
Several foreign navies operate anti-piracy patrols off the coast of the Horn of Africa nation, including European, US, Russian and Chinese forces.
Neighbouring Kenya has smaller vessels operating offshore from Kismayu, supporting its ground troops, who invaded southern Somalia last year, before joining the 17,000-strong AU force.
"I am deeply concerned by recent reports of civilian casualties in Kismayu caused by naval gunfire and air strikes," Bowden said.
"I reiterate my call for all parties to the conflict to make every effort to minimise the impact of conflict on civilians, and to allow full humanitarian access to all people in need," Bowden added in a statement.
The reports of the long-awaited assault come as the corruption-riddled government wraps up eight years of infighting, with a UN-backed selection process for new leaders due to be completed by an August 20 deadline.
Three Ugandan army helicopters en-route to Somalia to support the AU force crashed in Kenya on Sunday leaving seven soldiers dead.