Second time in a Month : Russian jet barrel-rolls over U.S. plane

A Russian SU-27 conducted a "barrel roll" Friday over the top of a U.S. Air Force RC-135 which was flying a reconnaissance mission in international airspace above the Baltic Sea, two U.S. defense officials told CNN.

The SU-27 approached alongside within 100 feet of the U.S. aircraft and then flew inverted over the top of the plane to the other side. The U.S. considers this a very unsafe aerial maneuver and is expected to voice its concerns to the Russians, one of the officials said.

This is the second barrel roll maneuver over a U.S. aircraft by the Russians this month. On April 14, a Russian jet "performed erratic and aggressive maneuvers" as it flew within 50 feet of a U.S. aircraft's wing tip, Danny Hernandez, a spokesman for U.S. European Command, said in a response to a question from CNN.

In that incident, an RC-135 aircraft also was intercepted by a Russian SU-27. The Russian SU-27 began the barrel roll from the left side of the U.S. RC-135 and went over the top of it to end on the right side of the aircraft, U.S. European Command said.

This also comes after two encounters earlier this month in the Baltic Sea between the Navy missile destroyer USS Donald Cook and two Russian jets. In one of those incidents, a Russian jet flew within 75 feet of the ship.