President Vladimir Putin, who marks 15 years in power this year, has said in a new documentary that Russia had proof that the United States helped separatists in the North Caucasus in the 2000s.

The Rossiya 1 TV channel is airing a two-hour long documentary on Putin on Sunday.

Following a disastrous war in the 1990s, Russia fought Islamic insurgents in Chechnya and neighboring regions in the North Caucasus.

In excerpts released shortly before the film's broadcast, Putin said Russian intelligence agencies had intercepted calls between the separatists and the US intelligence during the early 2000s, proving that Washington was helping them.

Putin was elected Russian president on March 26, 2000.