The United States has proposed a joint defense plan for Ukraine that would work like NATO’s collective security rules but operate outside the NATO alliance, according to a diplomatic source.

The idea came up during a conference call between US President Donald Trump, Ukrainian President Volodymyr Zelensky, and some European leaders, following Trump’s meeting with Russian President Vladimir Putin in Alaska.

Washington suggested “a non-NATO Article 5-style commitment” for Ukraine, meaning an attack on the country would trigger support from partner nations, similar to NATO’s collective defense principle.

Trump said he discussed this idea with Putin. NATO’s Article 5 states that an attack on one member is treated as an attack on all, forming the core of the alliance’s defense system.

The proposal was first mentioned in a private talk between Trump and Zelensky while the US president returned from Alaska, and later repeated in the group call with European leaders, including NATO Secretary General Mark Rutte.

Another source confirmed the NATO-like plan was discussed but expressed doubts about how it would work and why Putin, who opposes NATO, would agree to any system that protects Ukraine’s sovereignty.

Ukraine’s goal to join NATO has been a major concern for Moscow during the ongoing conflict, and some Western countries are reluctant to fully support Ukraine’s membership.

Trump has consistently ruled out the possibility of Ukraine joining NATO. President Zelensky is expected to visit Washington for talks with Trump, likely to discuss formats for a Trump-Putin-Zelensky meeting, Europe’s role in peace efforts, and possible security and territorial arrangements for Ukraine.