“Developments will be shared with the public.”Calling the explosion in Istanbul on Sunday afternoon an attack, Turkish President Recep Tayyip Erdogan said state authorities would work to identify those responsible for it.An investigation has been launched into the explosion, the country’s official Anadolu news agency reported.One eyewitness, journalist Tariq Keblaoui, told CNN that several people could be seen lying on the ground following the blast on Istiklal Street.The extent of the injuries of those he saw was not clear but several people were bleeding from their legs and arms, he said.Istanbul Mayor Ekrem Imamoglu called for assistance for police and health worker teams as they respond to the explosion in the city."