The arrest of three Russian scientists on suspicion of treason has been criticized by members of a Russian scientific institute, who warn the move has created a chilling effect in the community.
The three Russian scientists, Anatoly Maslov, Alexander Shiplyuk and Valery Zvegintsev, were detained by the country's security services in the past year, according to the open letter published this week by members of the Institute of Theoretical and Applied Mechanics (ITAM).
Their work included research into the development of hypersonic aircraft.
The letter appealed to Russian authorities to "protect Russian aerodynamic science," and warned that staffers not understand how to "do their job" for fear of being accused.
"Any article or report can lead to accusations of treason," it read.
"The work we're awarded for and lauded as examples for today becomes grounds for criminal prosecution tomorrow. In these circumstances, it's simply impossible for our institute to work," the letter also said.
According to the institute's website, Zvegintsev founded a laboratory that researches hypersonic technologies in 2001, and Shiplyuk took over the leadership of the laboratory in 2006.
Last summer, TASS reported that Shiplyuk and Maslov had been arrested in Moscow. According to the state news agency, both scientists were suspected of sharing state secrets related to hypersound.
On Tuesday, TASS also reported Zvegintsev, ITAM's chief researcher, had been placed under house arrest, citing a statement published by the court. That statement now appears to have been deleted form the court's website.
"The materials of all three criminal cases are closed from the public, but we know from open sources that the acts for which our colleagues can spend the rest of their lives behind bars are something that is considered essential all over the world, including in Russia," said the letter published by Zvegintsev's colleagues.
It added that "making presentations at international seminars and conferences, publishing articles in high-ranking journals, participating in international scientific projects" is part of "high-quality scientific activity."
"All of them (the three arrested scientists) are known for their brilliant scientific results. Their competencies and professional reputation allowed them to find a highly paid and prestigious job abroad, but they did not leave their homeland, devoting their lives to serving Russian science," the ITAM letter added.
On Wednesday, Kremlin spokesman Dmitry Peskov said he was aware of an appeal by scientists from the Siberian Branch of the Russian Academy of Sciences, but could not comment on it due to the ongoing investigation.