MOSCOW—Russian President Vladimir Putin said he and his Ukrainian counterpart were closing in on a cease-fire plan for eastern Ukraine, with Moscow proposing an end to the rebel offensive as well as a pullback of government troops—something that could be tough for Kiev to swallow.

In his own statements, Ukrainian President Petro Poroshenko said he "supported Russia's readiness to implement a joint plan for peaceful resolution" of the crisis, and that he hoped talks with separatists set for Friday will lead to the...