General Knud Bartels, who chairs NATO's Military Committee, said defence chiefs from the 28 nation alliance are set to review "future relationship with Russia and NATO's military posture".
"Central to our discussions will be the development and implementation of the alliance readiness action plan," the Danish general said, referring to the new initiative which includes rotating troops and equipment through facilities in Eastern Europe.
The meeting will also cover NATO's mission in Afghanistan and the situation in the Middle East, including the "pressing threat" from the Islamic State jihadists in Iraq and Syria, he added.
Lithuania said the new measures will also include regional "command and control" centres in the Baltic states and Poland.
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These countries were formerly behind the Iron Curtain and are concerned about Russia's territorial ambitions in the wake of the Crimea annexation and the conflict in eastern Ukraine.
Addressing the generals, including NATO top commander General Philip Breedlove, Lithuanian President Dalia Grybrauskaite today insisted the alliance needed to present "a clear deterrence" and that time was of the essence.
The NATO talks started hours after negotiators representing Kiev and Ukraine's pro-Russian separatists signed a new nine-point deal which includes creating a buffer zone in eastern Ukraine.
Face-to-face talk in the Belarussian capital of Minsk, less than 200 kilometers (124 miles) from Vilnius, ended with an agreement to pull back troops by 15 kilometers from current frontlines and to allow in OSCE pan-European security monitors to make sure the truce holds.
The West accuses Russia of supplying weapons to pro-Kremlin separatists battling Kiev government forces in eastern Ukraine but Moscow has repeatedly denied the allegations.