Call it “the insult at 35,000 feet.”

In a maneuver reminiscent of “Top Gun,” the Russian fighter jet pulled alongside the American reconnaissance plane high above the Baltic Sea. Then the jet rolled onto its belly to reveal an impressive arsenal of weapons. Finally, it screamed past the larger plane at a distance of just 20 feet — a minuscule margin of error at more than 1,000 miles per hour — only to repeat the trick moments later, according to reports.

If this were baseball, the April 7 incident would have been a brush-back pitch, high and tight enough to send a message.

But this ain’t baseball. And an increasing number of aggressive Russian acts in the air and at sea have led some experts to fear a new Cold War in the region.

“A chill has returned,” said Heather Conley, senior vice president for Europe, Eurasia and the Arctic at the Center for Strategic and International Studies. “It’s not a full-blown Cold War, but we are starting to see some new and troubling signs of Russian aggression.”

The Arctic and Baltic regions of Europe have borne the brunt of this newly resurgent Russia, Conley said.

“Immediately following Russia’s annexation of Crimea and in the subsequent months, we’ve seen a real uptick in Russian air incursions and maritime incursions,” she said. “Yes, nations periodically perform exercises and test things. That’s normal. But the numbers that we have seen just in this 12-month period [are not normal]. Some of the air incursions have doubled. They are coming into airspace, or coming extremely close to airspace.”

The April 7 flyby was only the latest in a long string of confrontations that Conley and other experts say are a sign of an emboldened Russia. A similar incident occurred a year ago on April 23, when a Russian fighter jet intercepted a U.S. reconnaissance plane in international airspace north of Japan. On July 18, an American surveillance plane was flying near Kaliningrad when Russian fighter jets reportedly chased it into Swedish airspace. And in September, Russian bombers practiced cruise missile strikes on the United States just outside of Canadian airspace.

The real concern, however, is that “we’re going to have an accident here if we’re not careful,” Conley said. Of particular concern were two cases in which Russian jets turned off their transponders — which allow other planes to see where they are — and nearly collided with commercial airliners above Sweden and Denmark. NATO recently reported spotting 19 Russian military aircraft flying over international airspace in Europe in just two days.

The incidents aren’t limited to the air. In October, Sweden scrambled dozens of ships and helicopters in an attempt to catch a Russian submarine that had allegedly strayed into Swedish waters. In November, the Scandinavian country announced that it had scientific proof of the Russian transgression.

Norway has also complained of an increase in Russian jets buzzing its shores, 27 percent from 2013 to last year. “Russia has created uncertainty about its intentions, so there is, of course, unpredictability,” the Norwegian defense minister, Ine Eriksen Soreide, recently told the New York Times.

Russia’s motives remain somewhat of a mystery, Conley said. On the one hand, the country owns more than 50 percent of the Arctic shoreline. Moreover, it’s no surprise Russia has sought to rebuild its military after the collapse of the Soviet Union.

“For many years, we kind of discounted Russia’s conventional military,” she said. “This is sending a message that Russia has not only modernized its military but is capable of projecting its power, so that we understand they see themselves in parity with the United States and NATO.”

Vladimir Putin has made projecting power a pet project of his since his return to the Russian presidency in 2012. He has annexed eastern Ukraine while accusing the United States of playing the aggressor. “The United States and its allies have crossed all possible lines in their drive to bring Kiev into their orbit. That could not have failed to trigger our reaction,” he said at a security conference Thursday. He has promised that Russia would build its own space station by 2023.

Most alarming, Conley said, is Putin’s recent admission that he weighed deploying nuclear weapons in Crimea if Russia met stiffer resistance.

“It’s this bravado and brinkmanship that is extremely concerning,” Conley said.

Whatever Russia’s intentions, the rise in confrontations reflects a real change in power in the region. “Europe’s military defense spending has atrophied significantly,” Conley said. “Russia’s actions kind of erode the credibility of western defenses, NATO defenses, territorial defenses. Perhaps [Putin] wants European leaders, particularly in the Baltics or Poland, to rise to his debate and take an action that would not be supported by others. It’s causing that instability or uncertainty. It doesn’t cross the threshold but it gets very very close to it.”

In the case of the April 7 incident, Russia denied that its pilot did anything wrong. But Conley said the country has as much, if not more, to lose than anyone should a flyby become something more. “They want economic development,” she said, but the uptick in military incidents is creating “instability or concern about the future of the Arctic.”

Conley says the Obama administration has been slow to react to the chill descending on northern Europe but that it seems to have recognized the issue.

“I think we need a more robust assessment of Russia’s capabilities, modernization and intent in the Arctic,” she said. “And we need to send some very clear messages privately and publicly to the Kremlin that we all want the Arctic to remain a place of international cooperation.”