World 100 metres champion Justin Gatlin says he is "shocked and surprised" by allegations in a British newspaper that his coach and an athletics agent offered to sell performance-enhancing drugs to undercover reporters. Anti-doping officials have launched an investigation into the claims about Gatlin's coach Dennis Mitchell and an agent, Robert Wagner while IAAF President Seb Coe says changes are needed. "We are looking at who we want in our sport," Coe, the 1500m gold medallist from the 1980 and 1984 Games, said in a statement. "The IAAF recognises as an industry we need to do more," said the Englishman. "Focusing on the influences that surround athletes is a critical area of work," Coe insisted.

World 100m champion Justin Gatlin. Pic/Getty images