Relatives of Ukrainian prisoners of war hold their portraits at a rally outside the Ukrainian President office in Kyiv, Ukraine, Thursday, Jan. 16, 2020. (AP Photo/Efrem Lukatsky)

Tatiana Gulevska, mother of a Ukrainian prisoner of war, cries during a rally outside the Ukrainian President office in Kyiv, Ukraine, Thursday, Jan. 16, 2020. (AP Photo/Efrem Lukatsky)

Relatives of Ukrainian prisoners of war hold their portraits at a rally outside the Ukrainian President office in Kyiv, Ukraine, Thursday, Jan. 16, 2020. (AP Photo/Efrem Lukatsky)

Demonstrators hold posters supporting Ukrainian prisoners of war during a rally outside the Ukrainian President office in Kyiv, Ukraine, Thursday, Jan. 16, 2020. (AP Photo/Efrem Lukatsky)

Relatives of a Ukrainian prisoner of war hold his portrait at a rally outside the Ukrainian President office in Kyiv, Ukraine, Thursday, Jan. 16, 2020. (AP Photo/Efrem Lukatsky)

Relatives of Ukrainian prisoners of war hold their portraits at a rally outside the Ukrainian President office in Kyiv, Ukraine, Thursday, Jan. 16, 2020. (AP Photo/Efrem Lukatsky)

Relatives of Ukrainian prisoners of war holding their portraits rally together with former prisoners at the Ukrainian President Volodymyr Zelensky's office in Kiev on January 16, 2020, to support prisoners held in the territories controlled by Russia-backed separatists in the country's east. (Photo by Sergei SUPINSKY / AFP)

Relatives of Ukrainian prisoners of war holding their portraits rally together with former prisoners at the Ukrainian President Volodymyr Zelensky's office in Kiev on January 16, 2020, to support prisoners held in the territories controlled by Russia-backed separatists in the country's east. (Photo by Sergei SUPINSKY / AFP)

Relatives of Ukrainian prisoners of war holding their portraits rally together with former prisoners at the Ukrainian President Volodymyr Zelensky's office in Kiev on January 16, 2020, to support prisoners held in the territories controlled by Russia-backed separatists in the country's east. (Photo by Sergei SUPINSKY / AFP)

Relatives of Ukrainian prisoners of war holding their portraits rally together with former prisoners at the Ukrainian President Volodymyr Zelensky's office in Kiev on January 16, 2020, to support prisoners held in the territories controlled by Russia-backed separatists in the country's east. (Photo by Sergei SUPINSKY / AFP)

Relatives of Ukrainian prisoners of war holding their portraits rally together with former prisoners at the Ukrainian President Volodymyr Zelensky's office in Kiev on January 16, 2020, to support prisoners held in the territories controlled by Russia-backed separatists in the country's east. (Photo by Sergei SUPINSKY / AFP)

Relatives of Ukrainian prisoners of war holding their portraits rally together with former prisoners at the Ukrainian President Volodymyr Zelensky's office in Kiev on January 16, 2020, to support prisoners held in the territories controlled by Russia-backed separatists in the country's east. (Photo by Sergei SUPINSKY / AFP)

Relatives of Ukrainian prisoners of war holding their portraits rally together with former prisoners at the Ukrainian President Volodymyr Zelensky's office in Kiev on January 16, 2020, to support prisoners held in the territories controlled by Russia-backed separatists in the country's east. (Photo by Sergei SUPINSKY / AFP)

Relatives of Ukrainian prisoners of war holding their portraits rally together with former prisoners at the Ukrainian President Volodymyr Zelensky's office in Kiev on January 16, 2020, to support prisoners held in the territories controlled by Russia-backed separatists in the country's east. (Photo by Sergei SUPINSKY / AFP)

Relatives of Ukrainian prisoners of war holding their portraits rally together with former prisoners at the Ukrainian President Volodymyr Zelensky's office in Kiev on January 16, 2020, to support prisoners held in the territories controlled by Russia-backed separatists in the country's east. (Photo by Sergei SUPINSKY / AFP)

Relatives of Ukrainian prisoners of war holding their portraits rally together with former prisoners at the Ukrainian President Volodymyr Zelensky's office in Kiev on January 16, 2020, to support prisoners held in the territories controlled by Russia-backed separatists in the country's east. (Photo by Sergei SUPINSKY / AFP)

Relatives of Ukrainian prisoners of war holding their portraits rally together with former prisoners at the Ukrainian President Volodymyr Zelensky's office in Kiev on January 16, 2020, to support prisoners held in the territories controlled by Russia-backed separatists in the country's east. (Photo by Sergei SUPINSKY / AFP)

Activists of far-right Azov party, relatives of Ukrainian prisoners of war and former prisoners rally at the Ukrainian President Volodymyr Zelensky's office in Kiev on January 16, 2020, to support prisoners held in the territories controlled by Russia-backed separatists in the country's east. (Photo by Sergei SUPINSKY / AFP)