When she heard her front door open almost two years ago, Kostiantyn Zinovkin’s mother thought her son had returned home because he forgot something. Instead, men in balaclavas burst into the apartment in Melitopol, a southern Ukrainian city occupied by Russian forces.

They said Zinovkin was detained for a minor infraction and would be released soon. They used his key to enter, said his wife, Liusiena, and searched the flat so thoroughly that they tore it apart “into molecules.” But Zinovkin wasn’t released. Weeks after his May 2023 arrest, the Russians told his mother he was plotting a terrorist attack. He’s now standing trial on charges his family calls absurd.

Zinovkin is one of thousands of civilians in Russian captivity. Ukrainian President Volodymyr Zelenskyy insists their release, along with prisoners of war, will be an important step toward ending the 3-year-old war.

So far, it hasn’t appeared high on the agenda in U.S. talks with Moscow and Kyiv.

“While politicians discuss natural resources, possible territorial concessions, geopolitical interests and even Mr. Zelenskyy’s suit in the Oval Office, they’re not talking about people,” said Oleksandra Matviichuk, head of the Center for Civil Liberties, which won the Nobel Peace Prize in 2022.

Thousands held

In January, the center and other Ukrainian and Russian rights groups launched “People First,” a campaign that says any peace settlement must prioritize the release of everyone they say are captives, including Russians jailed for protesting the war, as well as Ukrainian children who were illegally deported.

“You can’t achieve sustainable peace without taking into account the human dimension,” Ms. Matviichuk told.

It’s unknown how many Ukrainian civilians are in custody, both in occupied regions and in Russia. Ukraine’s human rights ombudsman Dmytro Lubinets has estimated over 20,000.

Ms. Matviichuk says her group received over 4,000 requests to help civilian detainees. She notes it’s against international law to detain noncombatants in war.

Oleg Orlov, co-founder of the Russian rights group Memorial, says advocates know at least 1,672 Ukrainian civilians are in Moscow’s custody.

“There’s a larger number of them that we don’t know about,” added Orlov, whose organisation won the Nobel alongside Ms. Matviichuk’s group and is involved in People First.

Detained without charges

Many are detained for months without charges and don’t know why they’re being held, Orlov said.

Russian soldiers detained Mykyta Shkriabin, then 19, in Ukraine’s Kharkiv region in March 2022. He left the basement where his family was sheltering from fighting to get supplies and never returned.

Ms. Shkriabin was detained even though he wasn’t charged with a crime, said his lawyer, Leonid Solovyov. In 2023, the authorities began referring to him as a POW, a status Solovyov seeks to contest since the student wasn’t a combatant.

Ms. Shkriabin’s mother, Tetiana, told AP last month she still doesn’t know where her son is held. In three years, she’s received two letters from him saying he’s doing well and that she shouldn’t worry.

She’s hoping for “a prisoner exchange, a repatriation, or something,” Ms. Shkriabin said. Without hope, “how does one hang in there?”

Terrorism, treason and espionage

Others face charges that their relatives say are fabricated.

After being seized in Melitopol, Zinovkin was jailed for over two years and charged with seven offenses, including plotting a terrorist attack, assembling weapons and high treason, his wife Liusiena Zinovkina told AP, describing the charges as “absurd.” While vocally pro-Ukrainian and against Russia’s occupation, her husband couldn’t plot to bomb anyone and had no weapons skills, she said.

Especially nonsensical is the treason charge, she said, because Russian law stipulates that only its citizens can be charged with that crime, and Zinovkin has never held Russian citizenship, unless it was forced upon him in jail. A conviction could bring life in prison.

Ukrainian civilian Serhii Tsyhipa, 63, was convicted of espionage and sentenced to 13 years in a maximum-security prison after he disappeared in March 2022 while walking his dog in Nova Kakhovka, in the partially occupied Kherson region, said his wife, Olena. The dog also vanished.

Tsyhipa, a journalist, was wearing a jacket with a large red cross sewn on it. Both he and his wife, Olena, had those jackets, she told AP, because they volunteered to distribute food and other essentials when Russian troops invaded.

Serhii Tsyhipa protested the occupation, and Olena believes that led to his arrest.

He was held for months in Crimea and finally charged with espionage in December 2022. Almost a year later, in October 2023, Tsyhipa was convicted and sentenced in a trial that lasted only three hearings.

He appealed, but his sentence was upheld. “But the Russian authorities must understand that we are fighting — that we are doing everything possible to bring him home,” she said.

Mykhailo Savva of the Expert Council of the Center for Civil Liberties said rights advocates know of 307 Ukrainian civilians convicted in Russia on criminal charges — usually espionage or treason, if the person held a Russian passport, but also terrorism and extremism.

He said that in Ukraine’s occupied territories, Russians see activists, community leaders and journalists as “the greatest threat.”

Winning release for those already serving sentences would be an uphill battle, advocates say.

Held in harsh conditions

Relatives must piece together scraps of information about prison conditions.

Zinovkina said she has received letters from her husband who told her of problems with his sight, teeth and back. Former prisoners also told her of cramped, cold basement cells in a jail in Rostov, where he’s being held.

She believes her husband was pressured to sign a confession. A man who met him in jail told her Kostiantyn “confessed to everything they wanted him to, so the worst is over” for him.

Orlov said Ukrainian POWs and civilians are known to be held in harsh conditions, where allegations of abuse and torture are common.

The Kremlin tested those methods during the two wars it waged in Chechnya in the 1990s and 2000s, well before invading Ukraine, said Orlov, who recently went to Ukraine to document Russia’s human rights violations and saw the pattern repeated from the North Caucasus conflicts.

“Essentially, a misanthropic system has been created, and everyone who falls into it ends up in hell,” added Ms. Matviichuk, the Ukrainian human rights worker.

A recent report by the U.N. Human Rights Council said Russia “committed enforced disappearances and torture as crimes against humanity,” part of a “systematic attack against the civilian population and pursuant to a coordinated state policy.”

It said Russia “detained large numbers of civilians,” jailed them in occupied Ukraine or deported them to Russia, and “systematically used torture against certain categories of detainees to extract information, coerce, and intimidate.”

Russia’s Defense Ministry, the Federal Penitentiary Service and the Federal Security Service did not respond to requests for comment.

Tempering hope with patience

As the US talks about a ceasefire, relatives continue to press for the captives’ release.

Liusiena Zinovkina says she hasn’t abandoned hope as her husband, now 33, stands trial but is tempering her expectations.

“I see that it’s not as simple as the American president thought. It’s not that easy to come to an agreement with Russia,” she said, reminding herself “to be patient. It will happen, but not tomorrow.”

Olena Tsyhipa said every minute counts for her husband, whose health has deteriorated. “My belief in his return is unwavering,” she said. “We just have to wait.”