NATO leaders are gathering in Ankara for a summit that's expected to be dominated by defence spending and alliance unity. US President Donald Trump accused some allies of failing to back Washington during the Iran war and questioned America's commitment to the alliance. His arrival follows NATO's announcement of billions of dollars in new arms deals. Al Jazeera’s Sinem Koseoglu reports from Ankara. Subscribe to our channel: bit.ly/AJSubscribe Follow us on Twitter: twitter.com/AJEnglish Find us on Facebook: facebook.com/aljazeera Check our website: aljazeera.com Check out our Instagram page: instagram.com/aljazeeraenglish Download AJE Mobile App: aje.io/AJEMobile #NATOSummit #NATO #Ankara #Turkey #DefenceSpending #MilitarySpending #ArmsDeals #NATOAlliance #AlJazeeraEnglish