At least two people were killed in a grenade attack in the Somali capital Mogadishu on Friday afternoon, police said.Police commissioner for Benadir region, Bashir Abshir Gedi, told reporters that the blast in Suka-holaha neighbourhood in Heliwa district took place when police and firefighters were in an emergency service to put out a fire in the area.The fire started from an electric shop and spread to its surroundings, Xinhua reported. "Firefighters from local government and the police successfully extinguished the fire that burnt seven shops in Suka-holaha area in Mogadishu, then Al-Shabaab militants hurled a bomb on the spot during the operation and killed two innocent civilians around the area," Gedi said.Investigations are underway into the attack and the fire, Gedi added.No one has claimed responsibility for the attack, but the militant group Al-Shabaab frequently carries out attacks in Somalia, mostly in Mogadishu, in its insurgency against the government.On Thursday evening, Al-Shabaab militants stormed a beach restaurant in Mogadishu, killing at least seven people.