Russian President Vladimir Putin (L) and Lyudmila Alekseyeva's son, Professor of Economics at Indiana University, Michael Alexeyev (alternative spelling Alexeev) (C) attend a memorial ceremony for Russian human rights activist Lyudmila Alexeyeva at the Moscow Journalist House in Moscow, Russia, 11 December 2018. Russian human rights activist, head of Moscow Helsinki Group and Soviet-era dissident Lyudmila Alexeyeva died at a Moscow's hospital on 08 December 2018 at the age of 91. EPA/ALEXEI DRUZHININ / SPUTNIK / KREMLIN POOL MANDATORY CREDIT 
Alexeyev is deputy head of the GRU, Russia's militaryintelligence. His boss, Igor Kostyukov, has been leading Russia's delegation in negotiations with Ukraine in Abu Dhabi on security-related aspects of a potential peace deal.
The Moscow prosecutor's office said Alexeyev, who was born in Soviet Ukraine,had been shot several times at a residential building in northwest Moscow by an unknown assailant who fled the scene.
Several senior Russian officers have been assassinated since the start of the war in Ukraine, with Moscow blaming the attacks on Kyiv. In some cases, Ukrainian military intelligence has claimed responsibility.
Since December 2024, three other officials of the same rank as Alexeyev, lieutenant general, have been killed in or near Moscow.
The attacks have angered Russia's influential war bloggers, prompting questions about why such senior people have lacked adequate protection. In at least two cases, the targets were killed right outside their homes.
The head of the General Staff's army training directorate, Lieutenant General Fanil Sarvarov, was killed by a bomb placed under his car on December 22.
Alexeyev was responsible for relations between the Defence Ministry and the Wagner mercenary group, led by Yevgeny Prigozhin, which fought in some of the fiercest battles in the early stages of the war in Ukraine.
Prigozhin was fiercely critical of the defence establishment and staged a mutiny in June 2023, when Alexeyev was one of the top officials sent to negotiate with him. The mutiny fizzled out, and Prigozhin died in a plane crash two months later.
(Reporting by Reuters; Writing by Gleb Stolyarov and Mark Trevelyan;Editing by Andrew Osborn and Kevin Liffey)