Defence Secretary Chuck Hagel on Friday welcomed Japan's agreement to relocate a US Marine base in Okinawa, calling it a move "critical" to Washington's rebalance to the Asia-Pacific region. The Pentagon chief hailed the approval by Okinawa's governor of a landfill permit for a new base called Camp Schwab in northern Okinawa to house the Marine Corps' Air Station Futenma, which is now situated in Ginowan, a densely populated area of the prefecture. "The realignment effort is absolutely critical to the United States' ongoing rebalance to the Asia-Pacific region and our ability to maintain a geographically distributed, operationally resilient, and politically sustainable force posture in the region," Hagel said in a statement. "Moving forward with this plan will reduce our footprint in the most populated part of Okinawa and let us return significant land south of Kadena Air Base while sustaining U.S. military capabilities vital to the peace and security of the region," he added. Kadena Air Base is also a U.S. Air Force base located in Nakagami District of Okinawa. The United States has 47,000 troops in Japan under a post-World War II security treaty. Some 18,000 Marines are stationed in Okinawa. The number will be reduced to about 10,000 once the new base is completed over the next decade, as some will be redeployed to Guam and Australia. "We look forward to continuing our work with Japan to implement our consolidation plan on Okinawa, and continuing our progress with relocating Marines to Guam and elsewhere in the Pacific," Hagel said. For years, Okinawans have groaned about pollution, noise and crime associated with U.S. bases on the island. Under a 2006 agreement, the Futenma base would be closed and its air operations relocated to Camp Schwab in the north, where a new airfield would be built. "Resolving these years-long issues will enable us to take our relationship to the next level as we revise the guidelines for U.S.-Japan defense cooperation," Hagel said. The agreement came following Hagel's visit to Japan in October and U.S. Vice President Joseph Biden's in December.