A large explosion has been heard in the Somali capital of Mogadishu, followed by accompanying gunfire, according to witnesses.

Reuters reported that the explosion, the whereabouts of which was not immediately known but seemed to come from the centre of the city, send a cloud of smoke bellowing into the sky above.

While no group immediately claimed responsibility for the explosion, Mogadishu has been plagued by violence linked to the extreme Islamist group al-Shabab, which took control of the city in 2006.

The country's UN-backed government has barely been able to impose its will beyond the confines of the national capital.

In February President Mohamed Abdullahi Mohamed was elected via indirect elections, Somalia's first since 2012, to deal with endemic national problem of al-Shabab violence and the spectre of widespread starvation brought on by the fighting. Al-Shabab has vowed to step up attacks against Mohamed's regime.

Refugees from drought have been streaming into Mogadishu in their thousands, overwhelming aid agencies. In the last 48 hours (21 March) at least 26 have died of hunger in the semi-autonomous southern region of Jubbaland.