WASHINGTON (CNN) -- A U.S. Air Force spy plane evaded an encounter with the Russian military in recent days by flying into nearby Swedish airspace without that country's permission, a U.S. military official told CNN.
The RC-135 Rivet Joint plane was flying in international airspace, conducting an electronic eavesdropping mission on the Russian military, when the Russians took the unusual action of beginning to track it with one of its land-based radar.
The Russians then sent at least one fighter jet into the sky to intercept the American aircraft, the U.S. official said Saturday.
The July 18 incident was first reported by the Swedish media group DN.se. There was no immediate reaction on the encounter from Russian officials.
The spy plane crew felt concerned enough about the radar tracking that they wanted to get out of the area as quickly as possible, the official said. The quickest route away from the Russians took them into Swedish airspace. The U.S. official acknowledged that was done without Swedish military approval.
As a result of this incident, the United States is discussing the matter with Sweden and letting them know there may be further occurrences where American jets may have to divert so quickly they may not be able to wait for permission.
Russian and U.S. aircraft often encounter each other, both in Northern Europe as well as the area between the Russian Far East and Alaska. But the official said the land radar activity by the Russians in this instance was unusual.
The ongoing civil unrest in Ukraine and the downing of a Malaysian airliner over eastern Ukraine on July 17 have heightened tensions between Washington and Moscow. Malaysia Airlines Flight 17 was brought down by a suspected surface-to-air missile, killing all 298 people aboard.
Pro-Russia rebels have denied allegations from Ukraine and the West that they shot down the Malaysian airliner, or that Russia supplied equipment used to shoot it down.
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