Defense Secretary Leon Panetta is in Asia this week for a weeklong tour. Panetta warns on China, N. Korea

Defense Secretary Leon Panetta warned Monday that China’s growing military demonstrates a “troubling lack of transparency” and is being “increasingly assertive” in the region.

“China is rapidly modernizing its military but with a troubling lack of transparency, coupled with increasingly assertive activity in the East and South China Seas,” Panetta wrote in an op-ed in Japan’s Yomiyuri newspaper, the Associated Press reports.


Panetta wrote that the United States and Japan will work together to “encourage China to play a responsible role in the international community,” the wire said.

The defense secretary is in Asia this week for a weeklong tour through Indonesia, Japan and South Korea.

In the op-ed in Yomiyuri, Panetta also sounded an alarm bell over North Korea, saying that Pyongyang “continues to engage in reckless and provocative behavior and is developing nuclear weapons and ballistic missiles, which pose a threat not just to Japan but to the entire region,” according to the AP.

The comments come as American and North Korean officials engage in talks this week about Pyongyang’s nuclear program in Geneva.

State Department spokeswoman Victoria Nuland said Monday that in these ongoing meetings, the U.S. is following up on the issues that were discussed with Pyongyang earlier this year.

“In July, we gave the North Koreans a specific set of initiatives that we’d like to see to demonstrate that they are prepared to take concrete steps to meet their denuclearization obligations,” Nuland told reporters. “We also asked at that time that North-South dialogue be resumed so I think we will … be following up on all of those things.”