Washington is reportedly rushing to complete an agreement with its most powerful NATO partners – the UK, Germany and France – on a set of security guarantees for Ukraine so the deal can be presented to the full bloc when the Western military alliance gathers for a summit this week in Vilnius.

The group’s power brokers have been holding “frantic, last-minute” negotiations to finalize their agreement on a security declaration for Kiev, Politico reported on Sunday, citing four unidentified officials familiar with the talks. The declaration would create an “umbrella” for all countries willing to provide ongoing military aid to Ukraine, even though details of the security commitments may vary from nation to nation.

The US, the UK, France and Germany have been discussing the issue with Ukrainian leaders for weeks and have “reached out” to other allies within NATO, the European Union and the G7, Politico said. The four governments aim to unveil their framework agreement at the summit in hopes that other members will join with them in the security pledges. The two-day event is scheduled to begin on Tuesday.