At least three people have died after a car bomb exploded at a busy junction in Somalia's capital, Mogadishu, according to city spokesman Salah Hassan Omar.

The explosion at a checkpoint near Somalia's parliament left several vehicles on fire.

The Islamist militant group, al-Shabab, said it had carried out the attack.

It has stepped up its campaign of violence in East Africa.

Ten days ago, the group killed about 90 people in another bomb blast in Mogadishu.

Over the weekend its fighters attacked a military base on the Kenyan coast, killing three American personnel and destroying several aircraft.

In response, Somali officials say al-Shabab positions have been hit in airstrikes.