A total of five individuals are being arraigned in a court in Moscow for last week's murder of Boris Nemtsov, a fierce critic of President Vladimir Putin.
The exact role of the suspects, both from the insurgency plagued North Caucuses region, is still unclear. Nemtsov, a fierce critic of President Vladimir Putin, was gunned down in Moscow last week.
Russian journalist Yevgenia Albats, who followed Boris Nemtsov's career for 27 years, says he was one of the few Russian political figures willing to directly criticize President Vladimir Putin.
Russia's president said Nemtsov's death was a shameful tragedy. Nemtsov was gunned down near the Kremlin on Friday. His supporters blame Russian authorities.
Russia has cut off Ukraine's gas supplies in the past and is threatening to do it again. The latest payment dispute comes at a sensitive moment in the crisis in eastern Ukraine.
Nemtsov served as a governor and deputy prime minister in the 1990s. He later became an opposition leader and sharp critic of Russian President Vladimir Putin. He was killed on a street in Moscow.
Ukraine's military says the withdrawal of 100-millimeter guns "is the first step" in a process that will be monitored by the Organization for Security and Cooperation.