NAIROBI - A large blast that wounded dozens of people in the centre of the Kenyan capital was likely caused by an electrical fault, Police Commissioner Mathew Iteere told reporters Monday. “We are able to prove it was not a grenade attack or bomb attack...from the preliminary conclusions we do think it was an electrical fault,” Iteere said, playing down fears it had been an attack by Somalia’s Al-Qaeda-linked Shebab insurgents. The blast, which ripped through a small shopping complex on Nairobi’s Moi Avenue in the early afternoon, left around 30 people wounded. An official at Kenyatta hospital said 27 people had been admitted there alone, with others ferried to other medical centres. Kenya has been hit by a wave of grenade attacks in recent months and the police have repeatedly blamed them on Shebab or its supporters. Minutes after the blast the pro-Shebab Twitter site Al-Kataib reported a “huge explosion in Nairobi” although it did not specifically claim any responsibility. Last month the hardline Shebab again warned Kenya of revenge attacks for sending tanks and troops into Somalia in October. Officials from the electricity company were investigating at the scene of the blast, where rescue teams were working to see if anyone remained trapped in the caved-in building. Police pushed back thousands of onlookers who thronged the surrounding roads.