At least seven people have been killed in renewed fighting between rival Somali warlords battling for control of the southern port city of Kismayo, the AFP news agency reports, quoting witnesses.

Gunmen from the Ras Kamboni militia of Ahmed Madobe, who last month appointed himself "president" of the southern Jubaland region, clashed on Wednesday with forces loyal to Bare Hirale, a former Somali defence minister who also leads a powerful militia army.

"Seven people, three of them civilians, were killed, and four others were injured," said Ali Mohamed, a resident of Kismayo said.

Kismayo was reportedly quiet on Thursday morning, but residents were nervous and said they feared further fighting.

Two days of heavy fighting earlier this month between Madobe's forces and gunmen loyal to Iftin Hassan Basto, another leader claiming to be president, left at least 31 dead and 38 wounded, according to the UN's World Health Organisation.

Several rival factions claim ownership of Kismayo, a former stronghold of the al-Qaeda-linked al-Shabab, where Kenyan troops in an African Union force are now based.

Kenyan troops, who invaded Somalia in 2011, back Madobe's control of the strategic and economic hub. However, neither the title of "president" nor the region of Jubaland is recognised by the weak central government in Mogadishu.

Somalia has been slowly emerging from two decades of war that have left the Horn of Africa nation in ruins, but Western governments and analysts say renewed fighting between armed groups can swiftly reverse the fragile gains.

Source: Agencies