Suspected WW2 bomb found on Murlough beach 3 November 2013 Last updated at 19:34 Police have sealed off a section of beach in County Down after two dog walkers discovered what is believed to be a World War Two mortar shell. Dawn Mitchell and her husband spotted the rusted object on Murlough beach on Sunday. She photographed it and sent her picture to the coastguard. The South Down coastguard arrived on the site a short time later, followed by the police who sealed off the area. Army bomb disposal officers have been tasked to examine the object. A coastguard spokesman said the object is now submerged due to the incoming tide and it could be the morning before a proper examination can take place. Ms Mitchell is an artist from Hillsborough, County Down, and was taking photographs of the Mourne Mountains from Murlough beach. Fins She said her dogs were playing in the sea when one of the animals jumped out of the water suddenly. Ms Mitchell looked down into the water to find out what had frightened her dog and saw what she thought was a "big fish." She said her husband "poked at it with a stick" but then stepped back and shouted: "It's got fins - it's a mortar!" The couple phoned the coastguard to report their discovery as there were other members of the public on the beach. Ms Mitchell said the coastguard asked her to take a photograph of the object to ensure they were not about to spark a false alarm, unintentionally. Mortar shell On receiving the picture, the coastguard asked the couple to move well away from the object but to remain on the beach so they could point out its location to coastguard crews. The South Down coastguard arrived on the beach a short time later and confirmed they thought it was a mortar. Police arrived shortly afterwards and sealed off a section the beach between Murlough and Newcastle. A PSNI spokesman said the operation was due to the "discovery of what is believed to be a World War Two mortar shell."