NATO members are set to agree to a goal to increase their defense spending level to 5% of their GDP as a means to address a long-held grievance by President Donald Trump.

At talks in Antalya, Turkey, NATO Secretary-General Mark Rutte said that more investment and military equipment are needed to deal with the threat posed by Russia and terrorism.

The debate on defense spending is heating up ahead of a summit of U.S. President Donald Trump and his NATO counterparts in the Netherlands on June 24-25. It’s a high-level gathering that will set the course for future European security, including that of Ukraine.