President Trump will push NATO allies to fulfill vital defense spending commitments at a summit in Turkey this week.
The pressure follows pledges secured from member nations last year.
NATO's chief has requested that allies submit plausible plans to reach spending benchmarks.
U.S. officials have characterized rising tensions as "growing pains."
Reports reveal allies will get "report cards" to track their progress.
Certain analysts have alerted of economic consequences if the demands are applied fully.