"They are expected to agree on a number of measures, including further improvements to the readiness of Allied forces, recognizing space as an operational domain, and updating NATO’s action plan against terrorism," said the statement.
"Leaders are also due to have a strategic discussion on Russia, the future of arms control, as well as the rise of China," it added.
Erdogan left for London early Tuesday and will hold quartet Syria summit with Macron, Merkel, and Johnson at 10 Downing Street later in the day.