What happened this week?published at 08:52 Greenwich Mean Time
A 29-year-old man from Uzbekistan has been arrested over the killing of a senior Russian general, Igor Kirillov, and his assistant in Moscow.
An explosive device hidden in an electric scooter was detonated remotely on Tuesday, authorities say, killing Lt Gen Igor Kirillov.
Ukraine claimed it was behind the attack, adding that Kirillov, 54, was "a legitimate target" who had carried out war crimes. The day before, Ukraine charged the Russian general in absentia, saying he was "responsible for the mass use of banned chemical weapons".
Russia's Federal Security Services (FSB) has published a video of the suspect's interrogation.
In it, a dark-haired man in handcuffs with what appears to be a visible rip in his coat, is heard saying in Russian that he was offered a reward and a European passport in exchange for killing Kirillov.
It is unclear whether the suspect's confession was made under duress.