NATO's deputy supreme allied commander in Europe has expressed hope that next month's summit in Turkey will encourage member states to increase defense spending, reaffirm support for Ukraine and demonstrate the alliance's unity despite growing challenges.

Air Chief Marshal John Stringer shared his expectations in an interview with The Associated Press in London, less than two weeks before the NATO summit in Ankara on July 7-8. The meeting is expected to test the unity of the 77-year-old military alliance at a time of increasing political uncertainty.

The alliance has faced fresh questions after US President Donald Trump sent mixed messages about America's military presence in Europe and repeatedly threatened to withdraw from NATO. His calls to annex Greenland and his friendly remarks about Russian President Vladimir Putin have also unsettled many European leaders.

Adding to the uncertainty, US Defense Secretary Pete Hegseth last week criticized NATO allies for not allowing their military bases to be used in strikes against Iran. He also announced a six-month review of US troop deployments across Europe.

In the United Kingdom, which traditionally provides NATO's deputy supreme allied commander, recent resignations of government ministers highlighted concerns over defense spending plans that critics say are not enough to ensure the country's security.

Stringer said NATO summits are important political events that showcase the alliance's solidarity. While acknowledging that disagreements are inevitable in an organization that has expanded over several decades, he stressed the importance of maintaining unity.

"Are we in one of those moments at the moment? Yes, we are," Stringer said during a military conference in London, where AP also spoke with other senior European military officials about their expectations and concerns ahead of the summit.