* African force says it repulsed the attack, killed 110 militants
* Al Shabaab says it killed 60 soldiers for loss of 16 fighters
* Residents hear huge blast, exchange of fire

 Somalia's al Shabaab Islamist militant group attacked a military base of Ethiopian soldiers serving with an African Union force on Thursday, with both sides saying they had inflicted a heavy toll on their opponents.
Al Shabaab said a suicide car bomb rammed the entrance to the base in the central town of Halgan and its fighters overran the site, killing 60 soldiers with the loss of 16 of its own militants.
"It was a huge blast. It destroyed the gate and parts of the base," Al Shabaab's military operations spokesman Abdiasis Abu Musab told Reuters.
The group's fighters exchanged fire with Ethiopian soldiers and repelled a counter attack by Djibouti troops deployed from another base in the area.
Al Shabaab regularly attacks AMISOM, which is made up of about 22,000 soldiers and police from African nations supporting Somalia's government and army in the fight against the al Qaeda-linked militants.
The group's insurgency aims to drive out AMISOM, topple Somalia's Western-backed government and impose its strict version of Islam on the Horn of Africa state.
Lieutenant Colonel Joe Kibet, spokesman for the African Union's AMISOM force, dismissed al Shabaab's toll as a "falsehood" but did not give a casualty figure.
"AMISOM forces killed 110 al Shabaab and captured a large cache of weapons," he told Reuters by telephone.
Residents in Halgan, which lies in a region about 300 km (around 190 miles) north of the capital Mogadishu, said they heard a huge explosion and heavy exchanges of gunfire shortly before dawn. Shots rang out at least an hour after the initial blast, they said.
"AMISOM has now retaken (the town) after regrouping. But the town is mostly deserted," resident Osman Gelle told Reuters by phone from Halgan. "I counted five civilian dead bodies. Stray bullets hit them in their houses."
He said he had seen four helicopters land. AMISOM has said it is starting to deploy helicopters with AMISOM to provide more rapid military support, after several bases came under heavy al Shabaab attack. It also uses helicopters to ferry casualties.
Casualty figures cited by officials and al Shabaab are usually wildly different.
In January, al Shabaab said it had killed more than 100 Kenyan soldiers in El Adde, a camp in Somalia and near the border with Kenya. The Kenyan military gave no exact toll.