(Adds al Shabaab's claim of responsibility)
MOGADISHU, Dec 14 (Reuters) - A suicide car bomber killed two people in the centre of Somalia's capital Mogadishu capital on Friday in a blast that appeared to target an African Union peacekeepers' convoy, police and residents said.
Security in Mogadishu has improved greatly since Islamist rebels allied to al Qaeda fled the capital more than a year ago, but the coastal city remains dogged by bombings and assassinations blamed on the militants.
The bomber struck on the Maka al-Mukaram road, a thoroughfare lined by construction sites and tea-rooms that last year was a frontline in the battle for control of Mogadishu.
"An AMISOM armoured convoy passed us and just after we heard a loud explosion. We looked back and saw thick smoke," Samira Hussein, who was travelling down the road in a minibus taxi, told Reuters at the blast site where the twisted wreckage of the car smouldered.
The blast killed the bomber and two civilians and wounded seven others, Abdifatah Sabriye, a senior police commander in Mogadishu's Waberi district, told Reuters.
The al Shabaab rebel group claimed responsibility for the attack, saying it was targeting the United States' head of counter terrorism in east Africa.
The group said on its Twitter feed (@HSMPress) that the official was injured as he was being driven to the presidential palace in a convoy of three armoured vehicles.
American diplomats in Nairobi were not immediately available for comment.
Locals said the street, which links the commercial K4 district with parliament, was quieter than usual as the blast happened during Friday prayers.
In late September, al Shabaab withdrew from the southern port of Kismayu, their last major urban stronghold, a retreat that signalled their demise as a quasi-conventional military force. The rebels vowed to step up a campaign of suicide bombings and hit-and-run attacks. (Reporting by Abdirahman Hussein, Abdi Sheikh and Duncan Miriri in Nairobi; Writing by Richard Lough; Editing by Angus Macswan and Jason Webb)