Leaders in Ukraine are passing a milestone on Saturday that none of them wanted to see or celebrate. They have been fending off the Russian invasion of their homeland for exactly 500 days. And, once again, they are asking their allies for help.

NATO countries have provided military and financial support since the beginning of the war. They are set to reinforce those commitments at a summit next week in Lithuania.

Ukrainian President Volodymyr Zelenskyy is expected to join the gathering. However, he said on Friday that there is little agreement over his country's future in the alliance.

Zelenskyy said, "We expect positive results -- or, at least, some steps that would bring us closer to a positive result. This is very important for the security of the entire world."

NATO Secretary General Jens Stoltenberg says the alliance is serious about its commitment and that members will create an official council to deepen political ties with Kyiv.

Stoltenberg said, "I expect allied leaders will reaffirm that Ukraine will become a member of NATO and unite on how to bring Ukraine closer to its goal."

However, some see a risk that could complicate efforts to build a united front.

On Friday, US officials announced a new military package that includes cluster munitions, which could pose a threat to civilians. Many countries around the world ban the use of the weapons, including some NATO members, but not the US, Ukraine or Russia.

US National Security Advisor Jake Sullivan defended the plan. He said, "We will not leave Ukraine defenseless at any point in this conflict, period."

He added that Ukrainian forces will use the munitions only for defending their own territory.