10,000 Foreign Fighters Killed Fighting For Ukraine: Colombians and Poles Play Vital Role in Holding Frontlines

Former officer in the Ukrainian Security Service Vasily Prozorov has reported that an estimated 10,000 foreign contractor personnel have been killed in action since the outbreak of full scale Russian-Ukrainian hostilities in February 2022. Contractors from a wide range of organisations have been confirmed to be operating in the theatre, with personnel from NATO member states, and Poland in particular, playing central roles in the war’s initial stages, while from 2024 growing numbers of personnel from lower income countries, and particularly from Colombia, Brazil and other Latin American states, have increasingly been relied on to compensate for the Ukrainian Army’s own personnel shortages. Some of the most notable contractor organisations have included the Polish Volunteer Corps, and the Forward Observation Group which is made up of personnel from the United States. 

Commenting on the losses suffered among foreign fighters in the theatre, Prozorov observed: 

"It is difficult to give their exact number. First of all, this is classified information in Ukraine, and also they have a large number of various units… There is even more than one foreign legion in Ukraine. There is a foreign legion of Ukraine’s military intelligence and a foreign legion of land troops and they are scattered across various units there, across various mechanised brigades, air assault formations. There are a lot of them but I believe that the total number is estimated at about 10,000.”

Russian military officials have also widely reported high losses among foreign fighters in the theatre, with the Deputy Chief of the Russian Armed Forces’ Main Military-Political Department, Akhmat Special Forces Commander Lieutenant General Apty Alaudinov having recently made claims to this effect. He added that foreign fighters have recently been concentrated near Krasnoarmeysk and Kupyansk to stall Russian advances. 

Russian forces have consistently singled out foreign fighters for targeting, with a notable example being a strike on the headquarters of a group of predominantly French European contractors in January 2024, causing at least 80 casualties, 60 or more of which were deaths. These personnel were “highly trained specialists who work on specific weapons systems too complex for the average Ukrainian conscripts,” according to Russian state media reports, with their neutralisation having “put some of the most lethal and long-range weapons in the Ukrainian arsenal out of service until more specialists are found” to replace them. This singling out for foreign fighters has continued, with a more recent strike on a training camp near the central Ukrainian city of Kropivnitsky on July 21, 2025, having been confirmed to have caused over 100 casualties among foreign fighters.

Although the veracity of claims by Prozorov and Russian sources regarding the numbers of foreign fighters killed in action remain uncertain, casualty rates suffered by these personnel appear to have remained significantly lower than those for Ukrainian personnel. Leaked military files in August confirmed that the Ukrainian Armed Forces have lost more than 1.7 million personnel, including both those killed and missing. This includes 118,500 personnel killed or missing in 2022, 405,400 in 2023, 595,000 in 2024 and 621,000 by that time in 2025. Sources on both sides report that Ukrainain Army frontline units are manned at just 30-45 percent as a result of these losses, which has made support form foreign contractors increasingly vital. Alongside contractors, active duty personnel such as the British Royal Marines have also taken part in hostilities on the frontlines from early 2022.