NATO foreign ministers on Thursday debated an American demand to massively ramp up defense investment as the United States focuses on security challenges outside of Europe.

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.

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.