LONDON — NATO Secretary General Jens Stoltenberg on Monday said the military alliance plans to toughen its stance toward China, while recognizing the need to work with Beijing on some global issues.

Speaking as he arrived in Brussels, Belgium, for a one-day NATO summit, the organization’s chief said: “The message is that, of course, there are opportunities in our relationship with China. For instance, on arms control and climate change we need to talk to China. At the same time, what we have seen over now several years is a significant military buildup by China, investing heavily in new military capabilities, including nuclear capabilities and also more advanced weapon systems.”

“We see coercive behavior, for instance in the South China Sea. And we also know that China does not share our values,” Stoltenberg continued. “China is coming closer to us. We see them in cyberspace, we see China in Africa [and] in the Arctic, but we also see China investing heavily in our own critical infrastructure and try to control it,” he said, referring to ports and telecom networks.

“We need to respond together as an alliance,” Stoltenberg said.

China’s embassy in London was not immediately available to comment when contacted by CNBC on Monday.

NATO’s Stoltenberg has described the summit as a “pivotal moment” for the alliance, with the group aiming to chart a course for the transatlantic relationship over the next decade and beyond.

His comments about China came shortly after the G-7 issued a joint statement calling on Beijing “to respect human rights and fundamental freedoms, especially in relation to Xinjiang and those rights, freedoms and high degree of autonomy for Hong Kong enshrined in the Sino-British Joint Declaration and the Basic Law.”

The G-7 communique on Sunday also underscored “the importance of peace and stability across the Taiwan Strait, and encourage the peaceful resolution of cross-Strait issues.”

China’s embassy in London said it was firmly opposed to mentions of Xinjiang, Hong Kong and Taiwan in the G-7’s final communique. It said the group’s message distorted the facts and exposed the “sinister intentions of a few countries such as the United States.”

“China’s reputation must not be slandered,” the embassy said on Monday, according to Reuters.

“It is certainly good to see the concerns articulated both about Xinjiang and Hong Kong, and to see commitment around combating forced labor,” Sophie Richardson, China director at Human Rights Watch, told CNBC when asked about the G-7’s joint statement on China.

“It would have been great to see some other additional steps, particularly coordinated targeted sanctions and the pursuit of an investigation into Xinjiang where we believe that crimes against humanity are taking place,” she added.

Earlier this year, the EU decided to impose sanctions against China for the “large-scale arbitrary detentions” of ethnic minority Uyghurs. Beijing, which denies that it violates Uyghurs’ human rights, retaliated by announcing countersanctions against members of the European Parliament.

The ethnic Uyghurs, who live mostly in China’s west, have been identified by the United Nations, United States, United Kingdom and others as a repressed group. China’s foreign ministry in March characterized such claims as “malicious lies” designed to “smear China” and “frustrate China’s development.”

The U.S., Canada and the U.K. issued a joint statement on March 22 in support of the EU’s move to impose sanctions.

“China’s extensive program of repression includes severe restrictions on religious freedoms, the use of forced labour, mass detention in internment camps, forced sterilisations, and the concerted destruction of Uyghur heritage,” the statement said.

The foreign ministers of the U.S., Canada and the U.K. said they were united in their “deep and ongoing concern regarding China’s human rights violations and abuses in Xinjiang.”

Separately, NATO’s Stoltenberg on Sunday told CNBC’s Hadley Gamble that the group would continue to build its military capabilities and employ a “wide combination of different tools” to counter Russian aggression.

“NATO’s approach to Russia is based on what we call a dual-track approach, defense and dialogue,” Stoltenberg said.

“And that’s exactly what we do when we now have implemented the biggest reinforcements of our collective defense since the end of the Cold War, and will continue to strengthen our collective defense with high readiness, more troops, and increased investment in our defense.”

U.S. President Joe Biden and Russian President Vladimir Putin will meet in person in Geneva, Switzerland on June 16.