Former German Chancellor Schroeder visited Putin's home on his 74th birthday.
The Kremlin said Putin spotted Schroeder in Moscow - there for a board seat at Russian supermarket chain Hyperglobus - and invited his "old friend" on October 7.
On the same day, Russia launched a mass attack on Ukraine, killing at least 32 people.
Zelensky called it the "birthday present" that Putin gave himself.