BRUSSELS (AP) — NATO's secretary-general is flatly rejecting accusations the alliance is fueling a Cold War-style rivalry with Russia, but says it must upgrade its military capabilities to be able to defend itself.

Jens Stoltenberg told reporters Wednesday "NATO will not be dragged into an arms race, but we must keep our countries safe."

The NATO chief spoke as alliance defense ministers gathered in Brussels for a meeting that is expected to increase the size of NATO's Response Force and streamline procedure for deployment of its new, ultrafast "spearhead" unit of 5,000 ground troops.

Moscow accuses NATO of threatening it by building up forces near its borders.

But Stoltenberg said NATO is only adapting to face today's realities, like Moscow's annexation of Crimea, large-scale Russian military exercises and a rash of nuclear rhetoric.