China's growing assertiveness and its cooperation with Russia pose a challenge not only to Asia but also to Europe, NATO Secretary General Jens Stoltenberg said Wednesday, AP reported.

According to Stoltenberg, "China is increasingly investing in nuclear weapons and long-range missiles without providing transparency or engaging in meaningful dialogue on arms control for atomic weapons, while escalating coercion of its neighbors and threats against Taiwan, the self-ruled island it claims as its own territory."

“The fact that Russia and China are coming closer and the significant investments by China and new advanced military capabilities just underlines that China poses a threat, poses a challenge also to NATO allies,” Stoltenberg told an audience at Keio University in Tokyo. “Security is not regional but global.”

“NATO needs to make sure we have friends,” he said. “It is important to work more closely with our partners in the Indo-Pacific.”

China is increasingly working with Russia, and they are fighting back authoritatively against a rules-based, open and democratic international order, he said.

At the same time, Stoltenberg said NATO does not consider China an adversary or seek confrontation and that the alliance will continue to engage with China in areas of common interest, such as climate change.