The plan would force the US and its European allies to intervene if Ukraine were attacked in the future - similar to Article 5 of the NATO Treaty, which considers an attack on a member to be an attack on the whole bloc.
A diplomatic source told AFP that during a phone call on August 16 between US President Donald Trump, Ukrainian President Volodymyr Zelensky and several European leaders - just hours after the Putin-Trump summit in Alaska, Washington had officially raised the idea.
Notably, Russian President Vladimir Putin is said to have agreed to this option.
The US has proposed a Article 5-style security mechanism but is not part of NATO, and President Putin has accepted, the source said. However, no one understands why he agreed, while Russia has always strongly opposed Ukraine's access to any real security guarantees," the source said.
Moscow has repeatedly affirmed that Ukraine's desire to join NATO was the reason for the conflict in 2022. President Trump has also ruled out Ukraine's ability to join NATO.
Analysts say that if the mechanism is not as binding as Article 5, Russia could consider it an acceptable concession, while helping President Trump achieve the historic treaty he is pursuing.
In a joint statement after the phone call with President Trump, the European leaders emphasized: "Russia cannot have the right to deny Ukraine's EU- NATO integration path."
European Commission President Ursula von der Leyen wrote in X: Strong security guarantees, protecting the vital interests of Ukraine and Europe, are paramount in any peace agreement.
Previously, in March, Italian Prime Minister Giorgia Meloni also proposed granting Ukraine the same security guarantees as NATO member states without a formal admission, considering this a more stable, long-term and effective choice than many other options.
Meanwhile, President Zelensky is expected to arrive in Washington, D.C. on August 18 for a direct discussion with President Trump. A second source told AFP that he will discuss the possibility of a Trump-P Putin-Zelensky summit, along with territorial issues, Europe's role and security guarantees.
