An explosion that occurred on Monday at the ground floor of a building close to Turkey's Taksim Square in Istanbul has left four people injured.The incident is most likely to have been caused by a cooking gas cylinder or home gas pipe explosion, Governor Hussain Avani Motalo told the local news broadcaster NTV.The blast also caused serious damage to nearby buildings.A municipality official added that it is thought that pressure on gas valves supplying an art exhibition in the premises could be the cause of the explosion.In the meantime, he stated that the condition of those injured remains uncertain.