CARDIFF, Wales, April 20 A British teenager putting up a fence for his neighbor in South Wales called the bomb squad after accidentally stumbling upon an anti-tank grenade.Martin Frampton thought the World War II anti-tank shell was just a hunk of rusty metal until he showed it to neighbor Keith Hartwell, who he was doing the job for, the South Wales Echo reported Friday.Hartwell thought it looked like a bomb and called the police and within a short time the bomb squad was on its way to the house."I was putting a post in when I dug down and hit something hard. I thought I was hitting a brick or something," said Frampton, 18. "The object was very rusty, but I didn't think anything of it." "I just put it to one side to show to Keith. When he saw it, he started shouting, 'it's a bomb'," he added. It turned out to be a World War II-vintage anti-tank grenade solid shot.Copyright 2007 by UPI