Somalia's al-Qaeda-linked al-Shabab rebels have claimed responsibility for the suicide explosion that killed a senior police chief in the north of the war-torn country, the latest in a string of attacks.

"With the blessing of Allah, the mujahedeen have carried out a successful operation targeting senior apostate officials," al-Shabab spokesman Abdulaziz Abu Musab said in a statement, boasting that three other policemen also died in the Monday's blast.

Government officials in Mogadishu confirmed Adirahman Abbas, police chief in the Bari region of Somalia's semi-autonomous Puntland region, was killed in the attack.

Abbas headed the police in Puntland's key port of Bosaso, the Bari region's main city. Officials confirmed that other police officers died in the blast, without giving an exact number.

Musab claimed the police chief was "targeted due to his crimes against Muslims... having imprisoned, tortured and killed many, thereby fulfilling the orders of the Crusaders."

Recent al-Shabab attacks in Somalia have targeted key areas of government and security forces in an apparent bid to discredit claims the insurgents have been weakened.

"God willing, everyone who treads his path will face a similar fate," Musab added.

Most of the recent al-Shabab attacks have been in the capital Mogadishu, over 1,000km to the south of Monday's bomb, but the group also have struck from bases in the rugged Golis mountains close by to Bosaso.

The mountain range, straddling the porous border between Puntland and self-declared independent Somaliland, is honeycombed with caves and difficult to access.

Source: Agencies