Children guarded by Hungarian police play on the ground after being detained along with other migrants who illegally crossed from Serbia to Hungary near the village of Asotthalom, Hungary, September 16, 2015. (Photo by Dado Ruvic/Reuters)

Refugees and migrants try to find a place on an already full train headed for Serbia, near the city of Gevgelija, The Former Yugoslav Republic of Macedonia, on February 24, 2016. Refugees and migrants from Iraq and Syria continue to pass through Macedonia on their way to the European Union. (Photo by Georgi Licovski/EPA)

The Eastern City Gate apartment buildings complex stands in the Konjarnik neighbourhood in Belgrade, Serbia, July 30, 2019. Brutalism, an architectural style popular in the 1950s and 1960s, based on crude, block-like forms cast from concrete was popular throughout the eastern bloc. (Photo by Marko Djurica/Reuters)

Aleksandra Krunic, of Serbia, drops to the court after defeating Petra Kvitova, of the Czech Republic, during the third round of the 2014 U.S. Open tennis tournament, Saturday, August 30, 2014, in New York. (Photo by Kathy Willens/AP Photo)

A boy wearing a World War II guerrilla cap with the five-point star attends the Victory Day ceremony in Belgrade, Serbia, Monday, May 9, 2022. People are marking the 77th anniversary of the victory over Nazi Germany in WWII. (Photo by Darko Vojinovic/AP Photo)

In this undated photo released Tuesday April 13, 2021, by Russian Defense Ministry Press Service, A Tu-160 strategic bomber of the Russian air force is shown on a training mission somewhere in Russia. Russian Defense Minister Sergei Shoigu on Tuesday described a massive military buildup in western Russia as part of drills intended to check the armed forces' readiness amid the threats posed by NATO. (Photo by Vadim Savitsky/Russian Defense Ministry Press Service via AP Photo)

A military cadet refreshes her lipstick before the National Day parade in Bucharest, Romania, Friday, December 1, 2023. Tens of thousands of people turned out in Romania's capital on Friday to watch a military parade that included troops from NATO allies to mark the country's National Day. (Photo by Vadim Ghirda/AP Photo)

Supporters of Ratko Mladic wave flags with his picture and reading in Serbian “Serbian hero” during a rally organized by the ultra nationalist Serbian Radical Party in front of the Parliament building on May 29, 2011 in Belgrade, Serbia. Some 7,000 supporters of the former Bosnian Serb army chief Ratko Mladic, who was arrested on Thursday in a village in Serbia after 16 years on the run, took to the streets of Belgrade, to hear speeches and protest Mladic's arrest. Mladic, who is facing extradition to the The Hague, is accused of war crimes, including the 1995 massacre of 7,500 Muslin men and boys in Srebrenica. (Photo by Srdjan Stevanovic/Getty Images)