President Trump will press NATO allies to fulfill key defense spending commitments at a summit in Turkey this week.
The coercion follows promises secured from member nations last year.
NATO's chief has requested that allies submit robust plans to reach spending benchmarks.
U.S. officials have characterized heightening tensions as "growing pains."
Reports show allies will obtain "report cards" to track their progress.
Various experts have cautioned of fiscal consequences if the demands are enforced fully.