He moved to Moscow in 1996 and joined President Boris Yeltsin’s administration where he rose quickly, becoming Acting President on 31 December 1999 when Yeltsin unexpectedly resigned. Putin won the subsequent 2000 presidential election, despite widespread accusations of vote-rigging,[3] and was reelected in 2004.”
“On 25 July 1998, Yeltsin appointed Vladimir Putin head of the FSB (one of the successor agencies to the KGB), the position Putin occupied until August 1999. He became a permanent member of the Security Council of the Russian Federation on 1 October 1998 and its Secretary on 29 March 1999.”