The 29-year-old was allegedly recruited by Ukrainian special services and promised $100,000 and travel to the European Union, said the news agency Tass, citing the country's domestic spy agency, the FSB.
The man was arrested in the village of Chernoye in the Balashikha district of Moscow, the news agency Ria reported, citing interior ministry spokesperson Irina Volk.
Kirillov, the head of the military's chemical, biological and radiological weapons unit, was killed along with his assistant when a bomb hidden in an electric scooter went off as the two men left a building in a residential area in south-east Moscow on Tuesday.
The Kremlin said the Ukrainian "Nazi regime" was behind Kirillov's killing. The Kremlin spokesperson, Dmitry Peskov, said: "We understand who our enemy is and what they are capable of. This once again proves the legitimacy of our actions during the special military operation."
The investigation was "progressing quite effectively", he added.
Denne historien er fra December 19, 2024-utgaven av The Guardian.
Start din 7-dagers gratis prøveperiode på Magzter GOLD for å få tilgang til tusenvis av utvalgte premiumhistorier og 9000+ magasiner og aviser.
Allerede abonnent ? Logg på
Denne historien er fra December 19, 2024-utgaven av The Guardian.
Start din 7-dagers gratis prøveperiode på Magzter GOLD for å få tilgang til tusenvis av utvalgte premiumhistorier og 9000+ magasiner og aviser.
Allerede abonnent? Logg på
Postecoglou claims coach's life is harder than being PM
A Premier League manager has a tougher job than the prime minister, according to Ange Postecoglou.
Rashford rebuked Players must talk to manager not media - Amorim
Ruben Amorim has said when he was a player he would have spoken to his manager about being dropped rather than react in the media, as Marcus Rashford has done.
Tonali double puts rampant Newcastle into last four
A sticking plaster for Newcastle's internal tensions or a potential long-term cure for their problems? Whatever the reality Eddie Howe's inconsistent team are a two-leg semi-final away from a potentially transformative Wembley showpiece after two stellar first-half goals from Sandro Tonali and another from Fabian Schär undid an immensely disappointing Brentford on Tyneside.
Jesus hat-trick delivers early Christmas gift as Arsenal topple Palace
It seems fitting that Gabriel Jesus should have chosen this time of year to end his goalscoring drought.
Elliott the difference as Rusk's Southampton put up late fight
It was a night that Simon Rusk will never forget, the one when he took charge of Southampton for the first time in the wake of Russell Martin's sacking and carried the fight to Arne Slot and Liverpool.
United circus has derailed Rashford but fresh start is no guarantee of success
It was two years ago yesterday that Argentina won the World Cup. England had gone out to France in the quarterfinals and, beyond the usual kneejerk attacks on Gareth Southgate, there was a sense of general optimism.
Maresca still 'trusts' Mudryk after failed drugs test
Enzo Maresca has thrown his support behind Mykhailo Mudryk, saying he believes the Chelsea winger's insistence that he is innocent of taking a banned substance.
Caldentey's late spot-kick secures first place for Arsenal
A late Mariona Caldentey penalty powered Arsenal to the top of Group C in the Champions League at Bayern Munich's expense after a Magda Eriksson double looked to have secured a draw for the visitors.
Taylor 'desperate' for a break as brilliant Barça take top spot from City
Manchester City's head coach, Gareth Taylor, says his team desperately need the upcoming winter break to bolster their squad, after they were comprehensively outplayed by a Barcelona side who reminded everybody why they are the reigning European champions with an emphatic win.
Freddie calls up Flintoff as teen makes the grade for Lions tour
Rocky Flintoff has been called up to his father's Lions squad for next month's tour of Australia, with England using the trip to give young bowlers who are already in contention for a place in the senior Test squad experience of local conditions before next winter's Ashes.
