At least two people have been killed and seven wounded when a bomb ripped through a busy market in the Somali capital, a government official said.

It is not clear who carried out Monday's attack but in the past similar explosions in Mogadishu have been claimed by al-Shabab fighters.

The group had previously vowed to wage a series of attacks during Ramadan, the Muslim fasting month which started on Sunday.

On Sunday, al-Shabab gunmen shot dead three people and said the killings were just the start of the group's Ramadan campaign, the Reuters news agency reported.