A suicide bomber strapped with explosives around his chest has killed at least 13 people outside a restaurant popular with Ethiopian and Somali troops in the town of Baladweyne in central Somalia, local officials said.

More than 10 people were also wounded in the explosion near a military base on Saturday, local legislator Dahir Amin Jesow told Reuters news agency by telephone from Baladweyne.

"A man with an explosives jacket entered unexpectedly in the tea shop where soldiers and civilians sat...and blew himself up," said local elder Ahmed Nur, speaking from the scene of the blast.

"I could see the bodies of several soldiers being carried, but I could not make out whether they were dead or injured."

No one immediately claimed responsibility for the attack.

Ethiopian troops have been fighting armed groups in neighbouring Somalia for much of the past decade.

Ethiopia waged an ill-fated war in Somalia in 2006-2009 and sent troops across the border again in 2011 to combat al-Qaeda-allied al-Shabab fighters, who were also battling Kenyan troops and an African Union military mission.

Reuters