Spain has asked to opt out of NATO¡¯s plan to increase members¡¯ defense spending to 5% of their gross domestic product, a move that could derail a summit at which the military alliance plans to ask them to commit to the target.

In a letter sent to NATO chief Mark Rutte on Thursday and seen by Reuters, Prime Minister Pedro Sanchez requested a ¡°more flexible formula¡± that either makes the spending target optional or excludes Spain from its application.

He said it was not Spain¡¯s intention to obstruct the outcome of next week¡¯s NATO summit. But any agreement to raise defense spending ¡ª a response to a request by U.S. President Donald Trump ¡ª would require unanimous approval by the 32 member states.