Suspected Al-Shabaab militants have attacked a Kenyan military camp in Kulbiyow, Lower Jubba, Somalia, some 18 kilometres from the Kenyan border.
The KDF base was attacked at 5am on Friday and the number of casualties remains unconfirmed.
"We are under massive attack and there is massive exchange of fire," military spokesman Lt-Col Paul Njuguna told Nation.co.ke
Although the military spokesman did not offer finer details on the exchange, he said the Kenyan troops had been pinned down.
Al-Shabaab fighters, the Voice of America reports, drove a truck filled with explosives and detonated them inside the base, followed by heavy gunfire and an infantry attack.
Al-Shabaab, Reuters reports, claimed it had killed 57 Kenyan soldiers, an allegation Lt-Col Njuguna denied.
"That is false," he told Reuters, in reference to Al-Shabaab's claim that 57 soldiers were killed although he did not give any casualty figures.
"The operation is ongoing. We are receiving updates," the officer added.
He denied claims that KDF camp had been overran by Al-Shabaab.
“Our soldiers repulsed the terrorists who had tried to access the camp using a Suicide Vehicle Borne Improvised Explosive Device,” Lt-Col Njuguna said in a statement.
The Kenya Air Force and the Kenya Army, he said, were undertaking an intensive pacification operation in the border town.
“Our soldiers remain vigilant and will continue to relentlessly pursue the terrorists to ensure secure Kenya and Somalia,” he said.
“It is important to note that the information peddled by the terrorists, our camp has not been overran,” he added.
The militant group has an elaborate propaganda machinery, with a spokesmen to boot, that fights to advance its war against the western-backed Mogadishu administration and its allies, including Kenya, Djibouti, Uganda and Ethiopia.
Sheikh Abdiasis Abu Musab, its military operation spokesman, had claimed they had also taken over the camp and seized weapons and military vehicles.
"We are pursuing the Kenyan soldiers who ran away into the woods," he told Reuters.
"Two mujahideen (fighters) rammed suicide car bombs into the base in Kulbiyow town before storming it," he said.
The Kulbiyow attack comes a year after Kenya lost over 100 troops when Al-Shabaab overran a KDF camp in El-Adde on the dawn of January 15, 2016.
Kenyan soldiers are fighting the rag-tag militia under the UN-backed African Union Mission in Somalia (Amisom) that has lost hundreds of soldiers in camp attacks.
Amisom is a 22,000-strong force comprising soldiers from Burundi, Djibouti, Ethiopia, Kenya and Uganda.
Besides Kenya, Al-Shabaab has attacked camps belonging to Uganda, Burundi and Ethiopia, with Uganda and Burundi suffering massive causalities.
Over the last two years Shabaab has rampaged through bases manned by Burundian soldiers in Lego, Ugandan troops in Janale and the Kenyans in El-Adde, inflicting high casualties and stealing military equipment each time.
The Kolbiyow raid is the second major attack this week in Somalia, coming three days after 28 people were killed when Shabaab bombers and fighters attacked a hotel in the capital.
Somalia is due to hold a presidential vote in early February, signalling the end of a drawn-out electoral process in which a new parliament has also been selected.
Political infighting and ongoing insecurity scuppered plans for a universal vote in 2016, with lawmakers elected by specially selected delegates.
Somalia has not had an effective central government since the 1991 overthrow of president Siad Barre's military regime, which ushered in more than two decades of anarchy and conflict in a country deeply divided along clan lines.
Opposition leader Raila Odinga, who wants Kenyan troops pulled out of Somalia, condemned the morning attack, calling it "unacceptable".
Separately, Kitutu Masaba MP Timothy Bosire (ODM) questioned whose interest the soldiers were serving in Somalia.
“I say pole (sorry) to those who lost their loved ones as we continue to suffer under [the] Jubilee leadership,” said the ODM treasurer.
Kenya, the lawmaker said, must rethink its occupation of Somalia in the fight against Al-Shabaab.
“The US, in its strategic interest, left Somalia and Kenyan soldiers should leave the war-torn country and secure our borders,” he said.
“For how long do we want to be in Somalia as our people continue to die?"
Mr Bosire said Kenya must strategically withdraw its troops from Somalia and operate within its borders.
“Kenya is becoming a failed state and I consider [the] Jubilee government a total failure in dealing with matters of security and the economy,” he said.
Mr Bosire had in April last year refused to stand up when President Kenyatta asked for a minute of silence in honour of KDF soldiers killed in the El Adde.
The incident later led to the withdrawal of his bodyguards before he sued in the High Court, which issued orders compelling the government to reinstate his security.
Reported by Stella Cherono, Justus Ochieng, Nyambega Gisesa, Fred Mukinda and AFP.