4 NATO countries are calling for a defense line along Europe's 700-mile border with Russia and Belarus

• The Baltic states and Poland have called for a defense line along Europe's border with Russia, per Reuters.
• They said it would protect the EU from Russia's "military" and "hybrid" threats.
• Frontline NATO countries are facing intensifying Russian hybrid warfare threats.

NATO member states Latvia, Lithuania, Estonia, and Poland have urged the EU to build defensive infrastructure along its 700-mile-long border with Russia and Belarus, according to Reuters.