Russia said Sunday that it scrambled fighter jets to prevent two U.S. strategic bomber planes from crossing its border over the Barents Sea in the Arctic. The U.S. military routinely carries out flights over international waters, operations that it says are conducted in neutral airspace and in accordance with international law. But Moscow has responded more aggressively to the exercises in recent months, warning in June that U.S. drone flights over the Black Sea risked leading to a “direct” military clash. The Russian Defense Ministry said it had scrambled fighter jets to intercept an “air tar…