Two Americans captured by Russian forces could face the death penalty. Can the US save them?

Less than two months ago, ​​the United States won the return of former U.S. Marine Trevor Reed from Russia, where he was serving a nine-year sentence for disputed assault-related charges, by exchanging him for a jailed Russian drug trafficker.

Now, a top Ukrainian official says his country is working toward a prisoner swap to free two U.S. military veterans captured by Russian forces while serving as war volunteers in Ukraine.

But while Ukrainian President Volodymyr Zelenskyy said he would fight for their release, some experts and former U.S. ambassadors say efforts to negotiate the men's return face far stiffer headwinds, citing a Russian desire to discourage war volunteers by punishing the men and U.S.-Russian diplomatic relations being at an all-time low.

“If (the Russians') goal is to discourage people from doing this, if their goal is to punish people who do this, they are not looking to release these people anytime soon,” said William Pomeranz, acting director of the Wilson Center’s Kennan Institute, which focuses on Russian and Ukraine research.

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If the Russians do negotiate, he said, they would demand “high prices in any potential swap.”

That could mean a more protracted effort to obtain the release of Americans Alexander John-Robert Drueke, 39, and Andy Tai Ngoc Huynh, 27, who were captured by Russian forces after coming under fire in the northeastern Kharkiv region on June 9.

“We've been telling all of our extended family members that this is a marathon,” Drueke’s aunt, Dianna Shaw, told USA TODAY.

Shaw, 55, said the U.S. State Department told her family that “every single avenue of communication is being employed” to reach the Russians in an attempt to negotiate their release.

State Department spokesman Ned Price said last week that officials had been in touch with authorities in Ukraine and Russia, but were not provided details about the men's whereabouts. Another spokesperson declined to comment further when reached by USA TODAY.

Will Russia agree to a prisoner swap?

The Russian military has said it considers foreigners fighting with Ukraine to be mercenaries not protected as combatants under the Geneva Conventions.

Russian spokesman Dmitry Peskov called the men “soldiers of fortune” whose fates would be decided by a court, but he would not rule out the death penalty, he told NBC News. “They should be punished," Peskov said.

While two Britons and a Moroccan were recently sentenced to death by Russian-backed separatists in eastern Ukraine, several experts told USA TODAY that Russia may be reluctant to further inflame tensions by allowing executions.

In an interview with USA TODAY last week in Kyiv, Major-General Kyrylo Budanov, chief of the Defence Intelligence of Ukraine, confirmed Russian media reports claiming U.S. citizens were being held in a prison in the Donbas and said, “We are working on it.”

"The way of resolving it is not easy," he said. "It's complicated, but we do see a way to resolve it. It will be more or less related to a prisoner swap. We have at our disposal people who the Russians want very much, who they need to get back very much.

"It also won't happen in a week or two. It will take a few months."

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Budanov declined to comment on how the Americans are being treated, for fear of jeopardizing ongoing efforts to secure their release.

Meanwhile, on Friday, Zelenskyy told NBC he would fight for their release, calling them “heroes.”

In an interview as part of the Aspen Ideas Festival, he said he was sure they'd return to their families, adding it was "a great honor that in the world there are some soldiers that are not afraid, and they came to support us and our sovereignty and independence," NBC reported.

'Uncharted territory' amid distrust between US and Russia

While the U.S. State Department and its embassies in Kyiv and Moscow are likely working to win their release, those efforts are hamstrung by the poor state of U.S.- Russia diplomatic relations, said William Tayor, a former U.S. ambassador to Ukraine and vice president of Russia and Europe at the U.S. Institute of Peace.

The U.S. has supplied billions in weapons to Ukraine and led an effort to enact financial sanctions on Russia following its invasion.

“The diplomatic interaction between the United States and Russia is at an incredible low. There is virtually no conversation going on,” he said.

In Pomeranz's view, "There is no reservoir of goodwill on the Russian side that wants to negotiate," he said.

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Melvyn Levitsky, a retired U.S. ambassador and professor of international policy at the University of Michigan, said prisoner-of-war swaps tend to be much easier to work out at the conclusion of a conflict. For now, the war in Ukraine shows no sign of ending.

And Levitsky said the war volunteers’ presence on a battlefield means a much more complicated set of negotiations in contrast to efforts to return figures detained on the basis of the Russian legal system, such as Reed or WNBA star Brittney Griner, who was detained at a Russian airport on Feb. 17 after authorities alleged that a bag search revealed vape cartridges containing cannabis oil.

Drueke and Huynh are believed to be the first Americans captured by Russian forces since the war began on Feb. 24.

“This is kind of uncharted territory,” Levitsky said. “My guess is that we'll work out something at some point. But remember, the Russians will have these prisoners as a kind of leverage."

Captured Americans wanted to help repel Russian invasion

Drueke, an Iraq war Army veteran, and Huynh, who served in the Marines, are both from Alabama, but didn’t know each other before they decided to travel to Ukraine in April to help repel the Russian invasion, according to their families. Drueke wanted to use his military experience to train Ukrainians on weapons, his family said.

Both families disputed Russian characterizations that they were “mercenaries,” noting they paid their own way to reach Ukraine to volunteer.

The two men disappeared around June 9 after a unit they were with came under heavy fire, relatives of both families told USA TODAY, saying they were told by members of the unit the men were accompanying.

Days later, Russian state television showed a video of the two men, confirming that they were taken captive. The Russian media report, citing Drueke, said the Americans became separated and surrendered to a Russian patrol.

Drueke, speaking into the camera from what appeared to be an office, sent a message to his mother, concluding with a quick wink:

“Mom, I just want to let you know that I’m alive and I hope to be back home as soon as I can be."

War volunteers warned of risks: US government 'not coming for you'

U.S. citizens have volunteered to fight in previous foreign conflicts, including the Spanish Civil War, the First Arab-Israeli War and Syria's civil war, said Nir Arielli, an associate professor of international history at the University of Leeds who studies transnational war volunteers.

“Here in Britain, the Foreign Secretary called on the Russian government not to execute two British foreign volunteers who were captured in Ukraine,” he said. “I expect Britain is using diplomatic channels to try to secure their release (but) the Russians are playing hardball.”

Jason Fritz, a lecturer at Johns Hopkins University who has interviewed some of the roughly 100 U.S. citizens who went to Syria to fight against ISIS, didn’t know of any who had been captured and subsequently returned to the U.S.

But he said some were warned before they left that rescues were unlikely if they were captured.

“The U.S. government's pretty clear that they're not coming for you," he said. "There's no special forces team that is going to come liberate you. It's not illegal, but they always try to dissuade people from doing it."

And while such volunteers could be serving as medics or trainers, as opposed to infantry soldiers, opposing forces aren't likely to recognize that distinction without hard evidence, Fritz said.

Shaw, Drueke’s aunt, said despite the tough words from Russian officials, she believes it shows “they know the world is watching. And that gives me more confidence that they will treat them as prisoners of war as they should.”

Joy Black, 21, Huynh’s fiancé, said she hopes they are treated according to the Geneva Convention, but so far she hasn’t had any word about their conditions. For now, she and her mother, Darla, say they will keep pressing to get the men safely home to Alabama.

“Obviously, we would like it to happen as soon as possible," Darla Black said. "We understand that there is a process and it's not immediate. We just have to take a day at a time."

Contributing: The Associated Press

Kim Hjelmgaard reported from Kyiv, Ukraine. Chris Kenning reported from Louisville, Kentucky. Kenning is a national news writer. Reach him at ckenning@usatoday.com and on Twitter @chris_kenning.

This article originally appeared on USA TODAY: Americans captured by Russians in Ukraine: Can US win their release?