Sergei Ivanov, a former Russian defense minister, Kremlin chief of staff and longtime ally of President Vladimir Putin, has died at the age of 73, the VTB United League basketball organization, where he served as honorary president, said Friday.

Sergei Ivanov, a former Russian defense minister once seen as a possible successor to President Vladimir Putin, has died. He was 73.

Sergey Ivanov served as honorary president of the VTB United League