SOCHI, Russia (REUTERS) - Russian President Vladimir Putin countered accusations on Tuesday that construction had polluted the 2014 Winter Olympic host city of Sochi, saying that preparations for the Games had boosted environmental quality in the area many times over.

"The ecological situation in the area has improved, not by a few percentage points, but by two or three, or by some indicators, four times," Mr Putin said during a meeting with the International Olympic Committee President Thomas Bach.

"All of this is on account of what has been done here," Mr Putin has staked his personal and political prestige on the Games and the drive to turn the Black Sea resort region of Sochi into not only an Olympic host city but also a world-class tourist destination, with a yacht marina and Formula 1 race track.

But environmental activists say that Olympic construction has polluted the nearby Mzymta River, produced waste that has been dumped near Sochi's water sources, and destabilised the ground around some building sites.

A Russian environmentalist who has tried to draw attention to damage caused by the work was detained on Monday.

Other environmental activists have had criminal cases opened against them and one, Suren Gazaryan, has received asylum in Estonia.

The Sochi 2014 organising committee says the construction work has been tailored to minimise harmful carbon emissions.

In a highly publicised stunt, Mr Putin also visited a sanctuary for the endangered Persian leopard, which is native to the region, posing for the cameras stroking one of the animals as it laid its paws on his lap.