Drug tests at February's winter Olympics in Sochi will be the toughest ever, Games chiefs have vowed.

Pressure is on to stop drug cheats after Russia's own testing laboratory was shut down by the World Anti Doping Agency. It was accused of not being ready to screen athletes effectively for banned substances.

International Olympic Committee president Thomas Bach said that the number of tests on competitors at the 2014 Games would be 57% higher than than previous events.

Athletes will undergo a total of 1,269 tests.

"We can clearly say that both as regards to quantity as well as quality this will be the toughest anti-doping programme we have ever had in the Olympic Games," said Bach.

"The tests will be even more target-oriented. There will be more tests pre-competition, where most of the anti-doping violations are happening."

The sports minister for Russia, Vitaly Mutko, moved to dampen worries about his country's readiness to enforce doping regulations by claiming that he was confident that Russia's own testing programme would improve.