ZAGREB (CROATIA) (AP):  The United States on Thursday delivered two Black Hawk military helicopters to Croatia, which is engaged in a mini arms race with neighbouring Russian ally Serbia amid simmering tensions in the post-war Balkan region.

The US Embassy in Croatia's capital, Zagreb, said the donated UH-60M multi-purpose helicopters will contribute to Croatia's growing defense capabilities and military preparedness in support of NATO.

The Black Hawk provides capabilities across a range of possible missions, from special operations to tactical troop transport to aeromedical evacuation, US Charge d'Affaires Mark Fleming said as the helicopters arrived on a US Air Force transport plane to Zagreb.

Croatia has earned a reputation as a committed and capable NATO ally, and the introduction of Black Hawks will further boost the capacities of the Croatian Armed Forces, Fleming said in the statement.

Defence Minister Mario Banozic thanked the US for the donation.

"It represents evidence of strong, friendly and allied relations, which are progressing every year, he said.

Croatia last month reached an agreement with the US to buy 89 Bradley fighting vehicles as part of cooperation with Washington and plans as a member of NATO to form an infantry brigade.

Croatia, which is also a member of the European Union, last year agreed to purchase 12 Rafale fighter jets from France.

Serbia, which was at war with Croatia in the 1990s over its secession from the Serb-led Yugoslavia, has lately been arming itself mostly with Russian and Chinese warplanes, drones, and anti-aircraft systems.

In recent months, Russia has handed over to Serbia 30 battle tanks and 30 armored personnel carriers.

Serbia has also recently purchased sophisticated Russian Pantsir air defence systems, as well as attack and transport helicopters and Chinese drones.

Although formally seeking EU membership, Serbia has refused to fully align its foreign policies with the 27-nation bloc and has worked on strengthening its relations with Russia and China in parallel.

With Croatia firmly standing by its NATO allies in the current tensions between Russia and Ukraine, Serbia said it will remain neutral.