NATO is taking these steps "as a response to the aggressive actions we've seen from Russia, violating international law and annexing Crimea," Stoltenberg says, adding, "We have to adapt our forces when we see the world is changing."
Stoltenberg insisted that the moves, likely to be approved by defence ministers in a meeting in Brussels, were purely defensive, but the increased presence on Russia's borders is likely to rile Moscow.
Other measures include establishing six regional command and control centres in eastern NATO countries and beefing up the alliance's command centre in the Polish city of Szczecin, Stoltenberg says.
The bases will be in the alliance's three Baltic states - Estonia, Latvia and Lithuania - plus Poland, Romania and Bulgaria.
"They will plan, organize exercises and they will be a key for connecting national forces with NATO reinforcements," the alliance chief said.
He also defends his decision to see Russian Foreign Minister Sergei Lavrov at this weekend's Munich Security Conference, stressing the importance of keeping "channels for political contact open," after NATO ended all practical cooperation with Moscow.
NATO leaders agreed to step up the alliance's eastern defences at a summit in Wales in September, amid concerns about Russia's actions in Ukraine and an increase in Russian military activity on NATO's borders.
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