WASHINGTON, June 7. /TASS/. NATO is in a constant search for an external enemy to justify the need of its existence, Daily Beast quoted Russian President Vladimir Putin as saying in an interview with Oliver Stone.

"There is no longer an Eastern Bloc, no more Soviet Union. Therefore, why does NATO keep existing? My impression is that in order to justify its existence, NATO has a need of an external foe, there is a constant search for the foe, or some acts of provocation to name someone as an adversary," Vladimir Putin said.

"Nowadays, NATO is a mere instrument of foreign policy of the US. It has no allies, it has only vassals. Once a country becomes a NATO member, it is hard to resist the pressures of the US," he continued. "And all of a sudden any weapon system can be placed in this country. An anti-ballistic missile system, new military bases, and if need be, new offensive systems."

"And what are we supposed to do? In this case we have to take countermeasures. We have to aim our missile systems at facilities that are threatening us," Putin said. "The situation becomes more tense."

The four-part documentary, The Putin Interviews, will be aired on CBS Showtime between June 12 and 15.