Amid tensions over a possible invasion of Ukraine, Russian aircraft intercepted U.S. Navy patrol planes in an “unprofessional” manner three separate times over the weekend, in one incident coming within five feet of an American plane, U.S. officials said Wednesday.

The Boeing-made U.S. P-8A aircraft are designed for anti-submarine and anti-surface warfare as well as intelligence, surveillance and reconnaissance missions, according to the Navy.

“The U.S. flight crews were flying in international airspace over the Mediterranean Sea at the time of these intercepts,” DOD spokesman Capt. Mike Kafka said in a statement Wednesday.

A U.S. official said it was unclear whether there was any connection with the large-scale Russian naval exercises being held in the Black Sea.

The incidents all happened in the same general area of the eastern Mediterranean over several days, a U.S. official told ABC News.

The U.S. has used diplomatic channels to raise its concerns to Russian officials, Kafka said.

“While no one was hurt, interactions such as these could result in miscalculations and mistakes that lead to more dangerous outcomes,” he added.

“The U.S. will continue to operate safely, professionally and consistent with international law in international waters and airspace,” Kafka said. “We expect Russia to do the same.”

ABC News’ Luis Martinez contributed to this report.