NATO Secretary General Mark Rutte said on Friday that the security guarantees agreement for Ukraine will consist of two layers: strengthening Ukraine’s army and commitments from the US and Europe aimed at deterring Russia in the event of future aggression.

On Tuesday, U.K. Prime Minister Keir Starmer hailed the possibility of NATO-backed security guarantees as a “breakthrough,” noting that the U.S. was now working “at pace” with 30 or so other countries, which he called a “coalition of the willing,” to help Ukraine.