During a visit in early September to the Albanian capital of Tirana, Kosovo President Vjosa Osmani accused Serbia, a close Russian ally, of attempting to destabilize the Western Balkans in order to “attack the values and the system of values on which the U.S. and NATO stand.”

Tensions have flared between the two countries of former Yugoslavia for much of the past two decades over different reasons. And Serbia, almost completely surrounded by NATO member countries, has been strengthening its military in recent years. Serbia, however, is not the only country with growing military power.

To determine the countries growing the most in military power, 24/7 Wall St. reviewed military strength scores from defense reference site Global Firepower — which uses an index composed of over 60 factors, including manpower, military equipment, finances, and membership in alliances such as NATO, to determine a country’s conventional fighting capability. We listed the 25 countries with the largest decline in their Global Firepower Index score — meaning an increase in military power — from 2016 to 2023. Only countries ranking within the 65 most powerful militaries as of 2023 were considered.

Lower Firepower Index scores indicate greater military strength. While a perfect score of 0.0000 is realistically unattainable based on the index criteria, the United States has the world’s most powerful military with a current GFI score of 0.0712. Despite having the most powerful military, the U.S. armed forces’ strength did not increase as much as other countries and the U.S. is not on the list. Meanwhile Serbia’s military, which now ranks 57th most powerful, ranked 82nd most powerful in 2016, as its military strength increased considerably. (See how Russia’s and NATO’s military capabilities compare.)

 Seven of the 25 countries with the greatest increases in military power are NATO members. And while all countries on this list increased their military power from 2016 to 2023, the theoretical fighting ability of three countries on this list — Brazil, Iran, and Spain — declined from 2021 to 2023 (as their GFI scores increased).

This list of the world’s growing military powers includes Finland, which joined NATO in April in the wake of Russia’s war in Ukraine. The Nordic country shares an 830-mile border with Russia, part of which is just 120 miles away from St. Petersburg, Russia’s second largest city. Ukraine, meanwhile, had the seventh largest increase in military strength and now ranks as the 15th most powerful in the world. (This nation spent a third of its economy on its military last year.)

Among these 25 countries, four are in Latin America, three are in Southeast Asia, and two are in Africa.

Here are the countries growing in military power.

Click here to see our detailed methodology.