Russian air power is making serious strides, and may soon be able to compete with U.S. and NATO dominance.

Gen. Frank Gorenc, commander of U.S. Air Forces in Europe, spoke to reporters about Russia's progress in air power development at the Air Force Association's annual Air and Space Conference and Technology Exposition on Monday.

"The advantage that we had from the air, I can honestly say, is shrinking, not only with respect to the aircraft that they're producing, but the more alarming thing is their ability to create anti-access, area denied areas is a challenge that we're all going to face up to," Gen. Gorenc said.

Improvements in Russia's air power include modernized surface-to-air missile defenses and remotely piloted aircraft. Russia has also shown significant gains in developing defenses against U.S. stealth fighters and bombers, developments Gen. Gorenc calls "alarming."

"I don't think it's controversial to say they've closed the gap in capability," Gen. Gorenc added, "we just need to be cognizant of it."

The Russian military has bolstered these new defenses around the Crimea region of Ukraine, which Russia annexed in 2014.

Gen. Gorenc says the U.S. Air Force needs to develop new training and tactical procedures to maintain the dominance of U.S. air power. The United States has maintained nearly uncontested air supremacy for decades, which provides additional protection for U.S. and allied ground operations, support Gen. Gorenc says the United States desperately needs to maintain.