Sergei Ivanov, former Russian defense minister and a prominent figure in President Vladimir Putin’s inner circle, has died at the age of 73. Ivanov, a member of the so-called “siloviki” cadre—security and intelligence officials who rose from the Soviet KGB—played a central role in shaping Russia’s post-Soviet security apparatus and defense policies in the early 2000s.

Ivanov’s death was initially reported by the VTB United League, a basketball organization where he served as honorary president, and later confirmed by the Kremlin. In a brief statement released on Friday, the Kremlin conveyed Putin’s “deepest condolences to the family and friends of Sergei Ivanov.”

Born in Leningrad (now St. Petersburg), Ivanov studied languages before joining the KGB, where he worked alongside Putin early in their careers. After the Soviet Union’s collapse, Ivanov advanced through the ranks of the KGB’s successor agencies, eventually serving as deputy director of the Federal Security Service (FSB) under Putin.

In 2001, Ivanov became Russia’s first civilian defense minister in modern history. During his tenure, he oversaw the armed forces amid the second Chechen war, launched by Putin to suppress separatist insurgency in the North Caucasus region. Ivanov’s term as defense minister marked a period of consolidation for Russia’s military and security structures.

He was known for his fluency in English and a combative style in international forums, notably at the Munich Security Conference, where he debated Western officials on security matters. Ivanov framed NATO’s expansion as a strategic threat to Russia and warned against the erosion of arms control agreements and U.S. missile defense initiatives. These concerns foreshadowed the Kremlin’s rationale for its actions in Ukraine, although that justification is widely rejected by Kyiv and Western governments.

Ivanov’s political influence peaked in 2005 with his appointment as deputy prime minister, and again in 2007 when he became first deputy prime minister. At that time, he was considered a leading candidate to succeed Putin, who was constitutionally barred from a third consecutive term. However, Putin ultimately endorsed Dmitry Medvedev as his successor. Ivanov continued to serve in high-level positions, including as Kremlin chief of staff, before being reassigned in 2016 to a lower-profile role as a presidential special envoy focused on environmental and transport issues—a move viewed by observers as a political demotion.

Russian Foreign Minister Sergei Lavrov paid tribute to Ivanov, describing him as an “outstanding statesman” who significantly contributed to Russia’s national security and defense modernization. Lavrov highlighted Ivanov’s efforts to strengthen Russia’s global position and reform its military-industrial complex.

Ivanov’s death closes a chapter on one of the key architects of Russia’s post-Soviet security state, whose career was deeply intertwined with the rise of Vladimir Putin and the political landscape of modern Russia.