NATO Secretary General Mark Rutte has indicated that Ukrainian President Volodymyr Zelenskyy's "Victory Plan" involves political and military issues that need to be addressed.

Zelenskyy on Wednesday presented his plan to end Russia's invasion to Ukraine's parliament.

One of the five points in the plan calls for an unconditional invitation to NATO that will officially begin the process of Ukraine's membership in the military alliance.

Rutte told reporters the same day: "As you know, at the NATO summit, Allies agreed that Ukraine's path to membership is irreversible, and Ukraine is closer to NATO than ever before."

He went on to say that Ukraine will join the alliance "when the time is right."

But he was cautious about expressing his support to the whole plan.

He said, "The plan has many aspects and many political and military issues we really need to hammer out with the Ukrainians to understand what is behind it, to see what we can do, what we cannot do."

NATO announced that Zelenskyy will attend the meeting of the alliance's defense ministers, which opens on Thursday. The meeting is expected to discuss his plan.