|Officers stand by the remains of a wrecked car at the scene of car bomb explosion along the "Kilometre 4" road junction, south of the capital Mogadishu, Somalia, May 5, 2013.|
The visiting delegation of Qataris, who were travelling in the Somali interior minister's bullet-proof vehicle, were "safe", a security officer told Reuters, without going into further detail. The minister was not in the car at the time.
The Islamist rebel group al Shabaab said it was behind the attack and threatened further strikes against Somalia's government, which it called a "puppet" of Western powers.
"More explosions are on the way," al Shabaab's military spokesman Sheikh Abdiasis Abu Musab told Reuters by telephone.
The al Qaeda-linked rebels have kept up a campaign of guerrilla-style attacks since the army and peacekeepers pushed them out of bases in the city.
Witnesses said a suicide bomber rammed a car laden with explosives into the convoy. The blast tore through the busy 'Kilometre 4' road junction in the centre of Mogadishu's commercial and administrative district.
Gunfire rang out immediately after the explosion as the convoy's security guards fired into the air to disperse onlookers.
Qatar has been forging closer political ties with Somalia in recent years as it seeks to expand its influence in the Horn of Africa region.
"The car bomb targeted delegates from Qatar. They are safe," Hassan Osman, a security official, told Reuters, adding that the minister's car was damaged in the blast.
The chairman of Mogadishu's Hodan district, where the blast occurred, told reporters at the scene eight people had been killed and five wounded, most of them civilians.
Sunday's bomb was a stark reminder of two decades of civil strife in a country where the central government depends heavily on a 17,600-strong African Union peacekeeping force for its survival.
While there has been a significant improvement in the coastal capital since African Union peacekeepers drove the Islamist al Shabaab group out of the city in 2011, the attack showed the relative ease with which the militants can still strike.
Some of Mogadishu's major roads were closed last week after security officials received a tip-off about an imminent attack, but were re-opened on Saturday.
The state of Somalia's security forces will top the agenda at conference in London on May 7. Britain and Somalia are hoping to use the event to drum up more international support at a time when al Shabaab are weakened as a fighting force but can still inflict devastating strikes.
Civil war after the fall of dictator Mohamed Siad Barre in 1991 left Somalia without effective central government and awash with weapons. The turmoil opened the doors for piracy to flourish in the Gulf of Aden and deeper into the Indian Ocean.
By Abdi Sheikh and Feisal Omar
MOGADISHU | Sun May 5, 2013 10:51am BST
(Writing by Richard Lough; Editing by Andrew Heavens)