At least four people were killed on Monday when a suicide bomber blew himself up in his car in an attack aimed at a senior police officer in Somalia's central Galkayo region, police said.
"There are at least five people dead, including the bomber," said Mohamed Abdullahi, a police officer in the town, which straddles the border between the northern breakaway state of Puntland and the self-proclaimed region of Galmudug.
Security sources said that a senior Puntland police official was wounded in the blast, but the reports could not be independently confirmed.
The violence is the latest in a string of attacks in the region, where tensions are high between rival political and clan groups.
Somalia's al-Qaeda-linked Shebab insurgents also operate in the wider area, and have carried out a series of guerrilla style attacks, but have tended to target mainly the capital Mogadishu.
The Shebab have claimed responsibility for most of the suicide attacks that have taken place in the past year.
Newly elected President Hassan Sheikh Mohamud, who took office in September after being chosen by the country's new parliament, faces multiple challenges in efforts to restore peace to the war-torn Horn of Africa nation.
Large parts of the country has been carved up by rival militia forces who have developed autonomous regions that pay little if any heed to the weak central government in Mogadishu.
But Shebab fighters are on the back foot, having fled a string of key towns ahead of a 17 000-strong African Union force, which is fighting alongside Somali government troops to wrest territory from the Islamists.
Ethiopian troops are also battling the Shebab in the south-west of Somalia.
The Shebab remain a potent threat, still controlling rural areas as well as carrying out guerrilla attacks in areas apparently under government control. - Sapa-AFP