As the specter of conflict with Russia looms 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 its capability 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. U.S. 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 cyberweapons would now have as big a role in NATO planning as guns and tanks.

The efforts seek to revamp a war-fighting structure that atrophied in the peacetime years after the Cold War. NATO was once a sprawling organization of 22,000 people and 33 commands. Following cuts in this decade, it shrank to 7,000 people and seven commands.

[Latvia’s cellphones stopped working. Russia’s war games may be to blame.]

"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, 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. U.S. 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.

The decision, which was widely supported by NATO's 29 member nations, would establish two new regional bases, bolstering NATO's total number to nine. No decisions were made about personnel numbers or where to station the new commands, although Germany and Poland are favorites for the logistics command and Portugal, the United States and France are possibilities for the sea-focused one.

The NATO nations that are most vulnerable to Russian attack said that the initiative would help improve their defenses. NATO nations deployed about 4,000 troops this year across the three Baltic nations of Estonia, Latvia and Lithuania, as well as Poland, which all share borders with Russia.

Any delay in speeding troops and materiel across Europe "means more casualties, additional risks and losses" in the event of war, Lithuanian Defense Minister Raimondas Karoblis said.

"Time is very important here," he said, adding that the speed with which NATO can respond to any Russian aggression could make the difference between fighting to defend NATO borders and a much more grinding effort to retake territory that has already been lost.

The decision to establish a ­cyber-operations center will widen NATO's ability to act not only against Russia but also other adversaries, such as the Taliban in Afghanistan and the Islamic State in Iraq.

[Russia held a big military exercise this week. Here’s why the U.S. is paying attention.]

NATO military commanders could use a cyberweapon to disable a Taliban website, for example.

Russia is suspected of using jamming technology in August to disable part of Latvia's cellular network ahead of its massive Zapad military exercises. And in the past, Estonia and Ukraine believe they have been targeted by Russian cyber tools.

"We now can strengthen NATO missions and operations also with cyber capabilities," Stoltenberg said. "We know that cyber will be an important part of any potential military conflict."

On Thursday, defense ministers are expected to discuss U.S. and NATO operations in Afghanistan and the effort to fight the Islamic State in Iraq and Syria. Troop commitments to NATO's Afghan operation are expected to go up by about 3,000, with half of the soldiers pledged from the United States and half from other NATO nations and partners.

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