China is adding more submarines to its fleet and is sending them farther out for longer time periods.

China now officially has more submarine vessels than the U.S., but they, however, are still inferior when compared to the U.S. fleet.

Vice Admiral Joseph Mulloy, deputy chief of naval operations for capabilities and resources, commented that the submarines are a part of China’s program of expanding into a larger number of geographic areas of operation for longer time periods. The Vice Admiral’s comments come as the latest expression of concern that has been voiced by some U.S. officials when regarding the Chinese military buildup.

U.S. military officials have recently dedicated themselves to highlighting the growing capabilities of China in an effort to make sure that the U.S. is fully able of maintaining its technical edge, though a recent Rand Corp. study managed to challenge some of those concerns when it discovered some “potentially serious weaknesses” regarding China’s military forces.