When Andy Huynh watched the news of Russia's invasion of Ukraine in February, he started losing sleep. All he could think about was the struggle of the Ukrainian people against an aggressor he felt was violating their sovereignty and opening the world up to a third World War.
"All my personal problems didn't feel important anymore … It felt wrong just to sit back and do nothing," he said. "I had to go."
The Alabama man was not alone. Two days after the invasion, Ukraine's President Volodymyr Zelenskyy called for "friends of Ukraine, freedom and democracy" to serve as volunteers in the Ukrainian military. More than 20,000 volunteers from 52 countries responded, many of whom had served in the U.S. Army, British Army, and, like Huynh, the U.S. Marine Corps, according to Ukrainian officials.
Their experience is credited by Zelenskyy for bolstering the war effort for Ukraine, especially since NATO countries have rejected sending ground troops in fears of starting their own conflict with Russia. Russian President Vladimir Putin announced in March that 16,000 volunteers from the Middle East would be joining his country's fight.
Tanya Mehra, a senior research fellow at the International Centre for Counterterrorism at The Hague, said the mobilization of foreign fighters on battlefields dates to 1816 and they have played prominent roles in conflicts in Afghanistan, Bosnia, Chechnya and Somalia since the 1980s.
The evolution of foreign-born fighters has created distinct classes of fighters, from mercenaries who join conflicts primarily for financial gain, Mehra said, and others who are driven by ideological reasons. Mercenaries, she said, who are outsourced contractors for small governments, tend to be associated to "increases in violence and higher civilian casualties," which can prolong the conflict, whereas foreign fighters become part of the state military, which makes them "accountable for the acts they have committed."
Many of those foreign fighters serving in Ukraine tend to be older than your average soldier, and in a stage in their lives where they felt they could help through their years of experience.
John Harding, 59, joined the Ukrainian military in 2018, when the country was fighting Russian-backed separatists. As a professional combat medic who served in Syria, the British-born Harding put his experience to use on the battlefield. But he also found he was in demand as a trainer for other medics who had no idea how to apply first aid in a hostile combat environment
"Medics are notorious for getting themselves killed," Harding said. "You may know how to apply a torniquet, but you also need to know how to apply a tourniquet while watching out for snipers."
One American, who did not want to use his name because he is still fighting in Ukraine, said he joined the Ukrainian military in April because he felt "it is important for the world to stand up with the Ukrainians and resist aggression." Having grown up in a military family and a U.S. Air Force veteran himself, the man took leave of his job in IT while living in central Europe to join the fight.
Today, he uses his background in engineering systems, cybersecurity and computer networks to operate drones in anti-tank and stinger missions. He said his squad was responsible for taking down a Mil Mi-28 Russian helicopter on July 18. The man said his homemade bombs and grenades are constructed using Coke cans and some of the 60 kilograms of TNT captured during an offensive in September. They take flight via off-the-shelf commercial drones.
The man said that the number of foreign fighters he encounters, the majority of whom were from the U.S., has decreased since the spring. The intensity of the fighting weeded away what he called the "TikTok warriors" who were not prepared for the danger, or length, of the missions. He remains fighting after seven months because of ideological reasons, but also because of the survivor's guilt he felt when two men from his squad -- Huynh and Alex Drueke, also from Alabama -- were captured on June 9 following a firefight.
"I felt I lost my two brothers. They followed me to this unit. I felt very guilty," he said. "Part of the reason I stayed this long is because of them."
Huynh and Drueke, a U.S. Army veteran, spent 105 days in captivity, including a month in a Russian "black site," where they endured daily torture. In late September they were released, along with eight other foreign-born volunteer fighters from England and Canada and more than 200 Ukrainian soldiers.
Harding was among those men released. He met Huynh and Drueke in a prison cell after having been captured in May when a Ukrainian unit he was with in Mariupol was forced to surrender. The torture he suffered has led to a diagnosis of permanent neurological damage to his hands, along with broken ribs and damage to his sternum. One aftereffect is "more psychological": "I have mood swings which I don't have control of," he said.
He now lives close to family in Luton, a town in the southeast of England. The results of ongoing medical treatment will determine his ability to work.
"Would I do it again? Knowing what I know, probably not. Would I do it again if I didn't know? Yes, I would," he said. "The only thing I would have done different is I wouldn't have surrendered. I would have fought to the very last round."
Like Harding, Drueke and Hyunh also say they have no regrets. Back home in Alabama, they are adjusting to their former lives. Hyunh is engaged and will marry soon, while Drueke is contemplating his next career move. They have bonded, not just with one another, but with Harding and the other men in their unit who are either still in Ukraine or returned home. One day they hope to reunite, either in the U.S. or in England -- or even Ukraine itself to help rebuild.
"Honestly, Ukraine has really surprised the world. We did not expect them to be that feisty, that strong, that determined," said Drueke. "They are amazing people."