Two years after Russian opposition politician Vladimir Kara-Murza’s arrest and conviction on terrorist charges viewed as politically motivated, U.S. lawmakers say they haven’t forgotten their “friend.”

At an April 9 conference in Washington organized to coincide with the anniversary of Kara-Murza’s arrest, the lawmakers said they will fight for him until he is released and called on the State Department to declare him wrongfully detained.

“We will continue to advocate for his immediate and unconditional release for as long as it takes,” Representative Jim McGovern (Democrat-Massachusetts), co-chair of the Congressional Human Rights Commission.

“We will continue to raise our voices. We will continue to have gatherings like this all throughout the country and all throughout the world,” he told those gathered, including Kara-Murza’s wife, Yevgenia, and two children.

Kara-Murza was arrested on April 11, 2022, upon his return to Russia following talks in the United States and Europe where he called President Vladimir Putin a war criminal for his decision to invade Ukraine.

Putin in March 2022 outlawed criticism of the war — which he calls a “special military operation” — and the armed forces as part of a sweeping post-invasion crackdown on freedoms.

A court sentenced Kara-Murza, 43, to a quarter-century in prison, the longest jail term handed to a Kremlin opponent in post-Soviet Russia and one more reminiscent of Stalinist times. The long sentence is symbolic of the harsher pivot Putin has taken since launching the war.

U.S. lawmakers, who were joined at the conference by European ambassadors, expressed deep concern about Kara-Murza’s fate in prison, highlighting the death of fellow opposition politician Aleksei Navalny in an Arctic prison in unclear circumstances in February.

Navalny, 47, was serving a 19-year sentence on extremism charges he and Western officials say were politically motivated.

“Russian prisons are notorious for their death toll,” McGovern said. “Sitting in a Siberian prison, Vladimir’s health is at risk. His life is a risk. And those in Russia with hope for a better future should not have to lose another leader to Putin’s fear and paranoia.”

Latvian Ambassador to the United States Maris Selga called on Western countries, especially the United States, to continue to support Ukraine militarily, saying Moscow’s defeat is critical to ushering in the democratic Russia that Kara-Murza is fighting for.

“As we support him and condemn his imprisonment, we must remain committed to stopping Putin and hold him accountable. This includes by supporting Ukraine in every way possible necessary until they achieve victory,” Selga said.

Representative Steve Cohen (Democrat-Tennessee), a member of the Congressional Helsinki Commission on human rights, expressed frustration that the State Department hasn’t declared Kara-Murza wrongfully detained despite multiple requests.

“We have written and we have written and we have written” to the State Department, he said.

RFE/RL has also pushed the State Department to designate its journalist, Alsu Kurmasheva, who has been jailed in Russia since last year, as wrongfully detained without success.

When a person is declared wrongfully detained, it activates various State Department offices and other U.S. government agencies to work together with colleagues inside and outside the government to develop a strategy to secure their release.

Sonata Coulter, the deputy assistant secretary of state overseeing policy toward Russia and Central Europe, said Secretary of State Antony Blinken as well as U.S. ambassadors to the United Nations, the Organization for Security and Cooperation in Europe (OSCE), and other international organizations consistently raise Kara-Murza’s case.

She did not comment on whether the State Department will declare him wrongfully detained. She said Kara-Murza was one of about 700 political prisoners in Russia.

“Russia’s internal repression enables its external aggression. These are inextricably linked, and we cannot address one without the other,” she said.

James Roscoe, deputy head of mission at the British Embassy in Washington, also said that U.K. diplomats continued to raise Kara-Murza’s case with Russian officials in Moscow and at the United Nations. Kara-Murza is a dual Russian and British citizen but has spent much time in the United States, where his wife and children live.

Kara-Murza played a leading role alongside his mentor, Boris Nemtsov — who was assassinated in 2015 — in persuading the U.S. Congress to pass groundbreaking sanctions legislation that targets corrupt officials and human rights abusers in Russia, including people close to Putin.

Kara-Murza believes he was twice poisoned deliberately in Moscow due to his lobbying for the legislation. In both of his illnesses, his Russian doctors indicated he suffered toxic effects of an “unidentified substance.”

In a sign of the legislation’s power to inflict economic pain, the Kremlin lobbied hard to prevent its passage and later sought its repeal.

Kara-Murza returned to Russia despite pleas by U.S. lawmakers and others not to. He told them he was a Russian politician and must be in the country to have an impact.

Since his arrest and conviction, he has been moved around in prison. In January, he was transferred to a punitive cell unit in a Siberian prison.

Unlike in regular parts of prisons where inmates can move around, work, visit a library or prayer rooms, or engage in other leisure activities, those incarcerated in punitive cells are isolated from the rest of the correctional facility.

His interaction with the outside world is through his lawyer.

“The worst fear of a political prisoner is to be forgotten,” Cohen told the audience. Kara-Murza “has not been forgotten.”