Aamin Ambulance service has become well known for being the first on the scene after a militant attack.Read more
Reporters in the Somali capital, Mogadishu, say a car bomb has exploded at a checkpoint by the national theatre in the city centre.
Some of them have tweeted photos of smoke rising over the city:
A pro-al-Shabab news website reports that the Islamist militant group says it is behind the bombing.
It is not clear if there are any casualties, but ambulances are at the scene, the news website Mogadishu-based Goobjoog reports.
Al-Shabab, which is linked to al-Qaeda, was forced out of Mogadishu in 2011 but continues to mount regular attacks in the city.
Smoke is seen rising above the Somali capital after a deadly suicide bomb attack.