The U.S. Embassy in Moscow has called for the immediate release of Nadezhda Savchenko, a Ukrainian helicopter pilot currently being held in a Russian detention facility on suspicion of having abetted the killings of two Russian journalists.
Savchenko was captured by separatists in Luhansk in June. She is now being held in the southern Russian city of Voronezh.
Ukrainian officials maintain that she was illegally trafficked across the border by Russian intelligence officers, while Russia maintains that she crossed the border voluntarily under the guise of a refugee.
Russian Investigative Committee spokesman Vladimir Markin said on Wednesday that Savchenko was believed to have provided crucial information that led to the deaths of journalists Igor Kornelyuk and Anton Voloshin of Russian public broadcaster VGTRK, who were killed by shelling in Luhansk on June 17.
Citing court orders, Markin said that Savchenko would remain behind bars until the end of August as an investigation runs its course.
The U.S. Embassy condemned Savchenko's "kidnapping by separatists, her illegal transfer to Russian authorities and her prolonged detention," U.S. Embassy Press Secretary Joseph Kruzich told Kommersant on Wednesday.
The embassy's condemnation echoed that of the Ukrainian Foreign Ministry's, which described Savchenko's transfer to Russia as "illegal trafficking" in a statement.
Ukrainian President Petro Poroshenko likewise referred to the incident as a "kidnapping" and ordered Prosecutor General Vitaly Yarema to investigate the circumstances of the case, according to a statement on Ukraine's National Security and Defense Council's website said.