Though NATO defense ministers appeared to agree to pursue a significant increase in member states' military spending to 5 percent of GDP, that should not be considered the sole voice of Europe, experts said, raising doubt on the goal's achievability.

The US and NATO leadership pushed to increase the alliance’s spending target from 2% of each member country’s GDP to 5%.

NATO member states signed off on the military alliance’s most ambitious military ramp-up since the Cold War as leaders closed in on an agreement to ratchet up spending at a summit later this month.