The Russian Air Force will continue its patrol missions of neutral waters despite worries of the United States, a high-ranking military commander said Monday.

Russia's patrol missions should not be of the U.S. concern, Air Force Commander Victor Bondarev told the media on the eve of the Russian Air Force Day.

"We implement our tasks. We prevent them in no way. I don't understand why they (the U.S.) are nervous," RIA Novosti news agency quoted him as saying. "We used to fly, are flying and will be flying."

Bondarev stressed the Russian strategic bombers did not enter the U.S. airspace during their near-border flights.

The U.S. North American Aerospace Defense Command (NORAD) said Thursday that it "visually identified" at least 16 incursions over the past week in and around the U.S. air defense identification zones conducted by Russian strategic nuclear bombers.

Russia has intensified military drills since the outbreak of Ukraine crisis. As clashes continue to rage in eastern Ukraine, Russia has been trading accusations with Western powers over the military build-up near its borders with Ukraine.