Russia on Wednesday detained a citizen of Uzbekistan who confessed to planting the bomb that killed Lt. Gen. Igor Kirillov in Moscow a day earlier on instructions from Ukraine's security service.

Kirillov, who was the head of Russia's nuclear, biological and chemical defence forces, was killed along with his assistant outside his apartment building when a bomb hidden in an electric scooter exploded. He was the most senior Russian military officer to be killed inside Russia by Ukraine.

SBU took responsibility for the murder

Ukraine's SBU intelligence service, which had accused Kirillov of being responsible for the use of chemical weapons against Ukrainian troops, a charge denied by Moscow, claimed responsibility for the killing.

Russia's Investigative Committee, which investigates serious crimes, said in a statement on Wednesday that the unidentified suspect had told them during interrogation that he had come to Moscow where he obtained an improvised explosive device for the attack.

He described how he had placed the device on an electric scooter, which he had parked outside the entrance of the apartment block where Kirillov lived, the statement said.

A camera was installed near Igor's house

Investigators quoted him as saying that he had installed a surveillance camera in a rented car nearby and that the organizers of the killing, who he said were based in the Ukrainian city of Dnipro, used the camera to monitor Kirillov and remotely detonated the device as he left the building.

The statement said the suspect, who was born in 1995, was offered $100,000 and residency in a European country for his role in the murder.

Investigators said they were identifying others involved in the attack and the daily Kommersant newspaper reported another suspect had been detained. Reuters could not independently confirm this.

How did Igor die?

Let us tell you that the top general of the Russian army, Igor Kirillov (54), died in a bomb blast on Tuesday morning. When he was leaving the building with the driver, an IED attached to an e-scooter parked outside exploded with a loud bang after the remote button was pressed, killing Igor along with the driver.

Russia talked about taking revenge

After Igor's killing, high-level meetings are being held on revenge with Russian military officials reviewing security preparations. Russia's former president and currently a senior security official Dmitry Medvedev said that now Ukraine's military and political leadership will have to pay for this. Moscow accused Ukraine of committing war crimes by killing several high-profile people and said that Kiev will be punished for this.