BRUSSELS — As tensions with Russia loom over Europe, NATO defense ministers decided Wednesday to expand the alliance’s operations for the first time since the Cold War, sharpen its focus on cyber operations, and boost their powers to respond to Kremlin aggression.
The moves came as tensions with Russia remain the highest they have been in the nearly three decades since the end of the Cold War. Defense Secretary Jim Mattis briefed fellow defense ministers Wednesday morning about Russian violations of the Intermediate Range Nuclear Forces Treaty, underlining the nuclear risk that is a worst-case consequence of the bitter back-and-forth.
Defense ministers approved plans that would bolster their ability to keep an eye on Russian submarines in the Atlantic Ocean, where crucial undersea communications are at risk of being cut. They committed to establishing a command dedicated to sweeping away barriers preventing their forces from being deployed quickly across Europe in the event of war. And they said that cyber weapons would now have as big a role in NATO planning as ordinary guns and tanks.
The efforts seek to revamp a war-fighting structure that atrophied in the peacetime years after the end of the Cold War. NATO was once a sprawling organization of 22,000 people and 33 commands. Following cuts earlier this decade, it shrunk to 7,000 people and seven commands.
‘‘Those decisions will ensure that NATO continues to adapt for the 21st century so that we can keep our people safe in a more challenging world,’’ NATO Secretary General Jens Stoltenberg said Wednesday at the meeting of ministers.
The holes that opened in NATO’s defense came as the alliance shifted in the years following the 1991 demise of the Soviet Union. Until Russia’s 2014 annexation of Ukraine’s Crimean Peninsula, NATO had turned into an alliance focused on limited deployments and operations far from its own territory. Now, with a conflict in eastern Ukraine still burning alongside NATO borders, leaders have returned to planning for a conventional war with Russia.
NATO commanders worry that even though their militaries are significantly stronger than those under the command of the Kremlin, Russia’s ability to rush its troops across its own territory give it a formidable practical advantage. US tanks were held up for hours over the summer as they waited for border clearance in Central Europe on the way to a military exercise. In some countries, requests to move troops and equipment need to be submitted up to 30 days in advance.
‘‘We are now much more focused on moving heavy equipment across Europe, because after the Cold War, we didn’t pay so much attention to that,’’ Stoltenberg said.