Sydney — A teenager was killed on Saturday after being attacked by a shark off Australia's east coast in the second deadly attack this month, police said.The victim, believed to be around 18 years old, was body boarding with friends about 100 meters offshore at Riecks Point, near the northern New South Wales city of Coffs Harbour, when he was bitten on the legs, New South Wales police said in a statement.The teen's friends got him back to the beach, and bystanders tried in vain to save him before paramedics arrived, a New South Wales ambulance police spokeswoman said. The teen, whose name has not been released, had serious injuries to his legs and suffered cardiac arrest. Paramedics tried to resuscitate him, but he was pronounced dead a short time later.There was no information immediately available on the type of shark involved.It was the second deadly attack in Australia this month. On Nov. 23, a 35-year-old surfer was fatally mauled by a shark off a beach near the Western Australia community of Gracetown. Three surfers have been killed in Gracetown in the past decade.Although sharks are common along Australia's coastlines, fatal attacks are relatively rare. The country has averaged just more than one fatal attack per year over the past 50 years.