Fighters from the al-Shabab group have attacked a base for African Union peacekeepers in southwestern Somalia, blasting their way into the compound and exchanging fire with peacekeepers, a Somali military official told Al Jazeera.

Dozens of al-Shabab fighters on Friday assaulted the military base, which is run by Kenyan troops who are part of the AU force in the town of El-Ade, not far from the Kenyan border.

"The troops are currently fighting the terrorists to push them back," LT. Col. Paul Njuguna, spokesman for African Union mission in Somalia told Al Jazeera.

"The counter-attack operation is still ongoing."

The assault started with a suicide car bomb, and then heavy gunfire was heard as fighters stormed into the base, he said.

'Dozens killed'

Al-Shabab said their fighters killed dozens of Kenyan troops in the attack.

"Mujahideen fighters from the 'Commander Saleh An-Nabhani Battallion' stormed the Kenyan Defence Forces' base in the town of Eel-Adde, Gedo region, over-running the base and killing more than 63 Kenyan crusaders." the group said in a statement seen by Al Jazeera.

However, the African Union denied the claim.

"Everyone is familiar with al-Shabab's propaganda. They will claim that they have taken over the camp even though they have not," Njuguna told Al Jazeera.

"Once we come to an end of this battle, we will have information on number of casualties and proper account of what happened."

The Kenyan army said it wasn't their base that was attacked but that of the Somali army.

"Al-Shabaab militia attacked the Somali National Army (SNA) camp which is in close proximity to Kenya Defence Forces (KDF) camp at Elade in Somalia," Kenyan army said in a statement.

"The SNA camp was overrun and the KDF troops under AMISOM counter-attacked in support of SNA." the statement added.

Despite being pushed out of Somalia's major cities and towns, al-Shabab continues to launch deadly guerrilla attacks across the Horn of Africa country.

The group, which has ties with al-Qaeda, has also carried out many deadly attacks inside Kenya.