UK Athletics chairman Ed Warner has claimed that the recent doping allegations "probably" extend further than Russian athletes.
A World Anti-Doping Agency independent commission has called for Russia to be banned from athletics competition due to alleged widespread doping, cover-ups and extortion.
The IAAF was implicated in the report, while the Russian government has been accused of complicity in doping and cover-ups.
"I suspect from jungle drums that beat that there are probably four, five or six nations that athletics really has a problem with," Warner told BBC Radio 5 live. "Russia's one. Athletics has probably got some other nations to root out."
The report also revealed that more than 1,400 samples were destroyed by a laboratory in Moscow.
