Enhanced Forward Presence (EFP) is a NATO-allied forward-deployed defense and deterrence military force in Central and Northern Europe. This posture in Central Europe through Poland and Northern Europe through Estonia, Latvia, and Lithuania, is in place in order to protect and reassure the security of NATO's Central and Northern European member states on NATO's eastern flank. Following Russia's invasion of Crimea and its War in Donbas, NATO's member states agreed at the 2016 Warsaw summit to forward deploy four multinational battalion battle groups to those NATO member states perceived to be most at risk of a possible Russian attack or invasion.