Vladimir Putin called on sports officials to carry out an internal investigation into allegations that Russia engages in extensive, state-sponsored doping.

But Russia's president said that clean athletes should not be punished for the actions of those who take banned drugs.

Mr Putin's comments came at a late-night meeting in Sochi, the city that hosted the 2014 Winter Olympics.

They reflected concerns that Russia's track and field athletes could be hit with a blanket ban for next year's summer Games in Rio de Janeiro.

Mr Putin ordered sports minister Vitaly Mutko and "all colleagues connected with sport" to pay close attention to the doping allegations and for an internal investigation to be conducted - one that guaranteed full co-operation with international anti-doping bodies.

"The struggle with doping in sports, unfortunately, remains a pressing issue and it requires unending attention," he said.

However, Mr Putin also drew a clear distinction with clean athletes.

"It's absolutely clear that athletes who stay away from dope ... shouldn't be held responsible" for those who use performance enhancing drugs, he said.