U.S. Defense Secretary Robert Gates says Washington recognizes that China played a constructive role in lessening tensions on the Korean Peninsula in the latter part of last year.

Gates made the remark to reporters aboard a plane on Sunday en route to Beijing.

Gates also said that China appears to have made more progress in building its first stealth fighter jet, the J-20, than previously thought, adding that such a move is worrisome.

On the planned visit by Chinese President Hu Jintao to Washinton on January 19th, Gates said he believes "a positive constructive, comprehensive relationship between the United States and China is not just in the mutual interests of the two countries, it's in the interest of everybody in the region and across the globe."