For the second time in less than a month, a Russian fighter jet conducted a barrel roll over a U.S. spy plane in the Baltic Sea Friday, flying within just 100 feet of the aircraft, a senior U.S. defense official told Fox News.

The Russian Su-27 zipped past the U.S. RC-135 surveillance plane in international airspace, the official said.

In the first barrel roll, on April 14, the jet flew within just 50 feet of the spy plane, Capt. Jeff Davis, a Pentagon spokesman, told reporters.

Russian aircraft have conducted a series of daring maneuvers calling out U.S. forces in recent weeks. Video on April 11 captured two Russian jets zooming past the USS Donald Cook, a Navy destroyer in the Baltic, flying only 100 feet off the ground. A U.S. defense official called it a "simulated attack profile."

Secretary of State John Kerry responded, "We condemn this kind of behavior. It is reckless. It is provocative. It is dangerous." He said forces on the destroyer could have shot down the jets under U.S. military rules of engagement.

But a Russian defense spokesman said the jet pilots carefully turned around. Maj. Gen. Igor Konashenkov claimed he didn't understand the "distressed reaction of our American counterparts."   

The Pentagon called the first barrel roll "unsafe and unprofessional." 

Fox News' Jennifer Griffin contributed to this report.