NATO Secretary General Jens Stoltenberg speaks with U.S. President Joe Biden during a bilateral meeting on the sidelines of a NATO summit at NATO headquarters in Brussels, Monday, June 14, 2021. U.S. President Joe Biden is taking part in his first NATO summit, where the 30-nation alliance hopes to reaffirm its unity and discuss increasingly tense relations with China and Russia, as the organization pulls its troops out after 18 years in Afghanistan. (Stephanie Lecocq, Pool via AP)

By AAMER MADHANI, JONATHAN LEMIRE and LORNE COOK Associated Press

BRUSSELS (AP) — NATO leaders targeted China in a strongly worded warning Monday, declaring the nation poses a constant security challenge, is trying to undermine world order and is working on nuclear missile development at a worrisome pace.

In a summit statement, the leaders said that China’s goals and “assertive behavior present systemic challenges to the rules-based international order and to areas relevant to alliance security.” The warning to China comes as President Joe Biden has stepped up his effort to rally allies to speak in a more unified voice about China’s human rights record, its trade practices and its military’s increasingly assertive behavior that has unnerved U.S. allies in the Pacific.

While the 30 heads of state and government avoided calling China a rival, they expressed concern about what they said were its “coercive policies,” the opaque ways it is modernizing its armed forces and its use of disinformation.

They called on Beijing to uphold its international commitments and to act responsibly in the international system.

Biden, who arrived at the summit after three days of consulting with Group of Seven allies in England, pushed for the G-7 communique there that called out what it said were forced labor practices and other human rights violations impacting Uyghur Muslims and other ethnic minorities in the western Xinjiang province. The president said he was satisfied with the communique, although differences remain among the allies about how forcefully to criticize Beijing.

Biden has used his eight-day trip to Europe to urge allies to work more closely in pressing Russian President Vladimir Putin over his government's treatment of political dissidents and to do more to stem cyber attacks originating from Russia that have targeted private companies and governments around the globe.

The new Brussels communique states plainly that the NATO nations “will engage China with a view to defending the security interests of the alliance."

But as Biden faced with the G-7 communique, some allies bristled at the NATO effort to speak out on China.

German Chancellor Angela Merkel said NATO’s decision to name China as a threat “shouldn’t be overstated” because Beijing, like Russia, is also a partner in some areas. China is Germany's top trading partner and is heavily dependent on Russia in fulfilling the country's energy needs.

Merkel noted that “when you look at the cyber threats, the hybrid threats, when you look at the cooperation between Russia and China, you can’t just ignore China.”

But she added that it was important to “find the right balance” as China is also a partner on many issues.

“I think it’s very important, just like we do in Russia, to always make the offer of political discussions, political discourse, in order to come up with solutions,” Merkel said. “But where there are threats, and I said they’re in the hybrid field too, then as NATO you have to be prepared.”

The Chinese Embassy to the United Kingdom on Monday issued a statement saying the G-7 communique “deliberately slandered China and arbitrarily interfered in China’s internal affairs,” and exposed the “sinister intentions of a few countries, such as the United States.” There was no immediate reaction from the Chinese government to the new NATO statement.

Biden arrived at his first NATO summit as president as leading members declared it a pivotal moment for an alliance beleaguered during the presidency of Donald Trump, who questioned the relevance of the multilateral organization.

Shortly after arriving at the alliance's headquarters for the first NATO summit of his presidency, Biden sat down with NATO Secretary General Jens Stoltenberg and underscored the U.S. commitment to Article 5 of the alliance charter, which spells out that an attack on one member is an attack on all and is to be met with a collective response.

“Article 5 we take as a sacred obligation,” Biden said. “I want NATO to know America is there.”

It was a sharp shift in tone from the past four years, when Trump called the alliance “obsolete" and complained that it allowed for “global freeloading” countries to spend less on military defense at the expense of the U.S.

Biden was greeted by fellow leaders with warmth and even a bit of relief.

Belgium Prime Minister Alexander de Croo said Biden’s presence “emphasizes the renewal of the transatlantic partnership." De Croo said NATO allies were looking to get beyond four stormy years under the Trump administration and infighting among member countries.

“I think now we are ready to turn the page," de Croo said.

Italian Prime Minister Mario Draghi made a not-so-subtle dig at Trump, while welcoming Biden.

“This summit is a continuation of yesterday’s G-7 and is part of the process of reaffirming, of rebuilding the fundamental alliances of the United States that had been weakened by the previous administration,” he said. “Think that President Biden’s first visit is to Europe and try to remember where President Trump’s first visit was?"

Trump's first overseas visit as president was to Saudi Arabia.

Trump routinely berated other NATO countries for not spending enough on defense and even threatened to pull the U.S. out of the world’s biggest security organization and even questioned the mutual defense provision of the NATO charter, a central tenet of the alliance.

The alliance also updated Article 5 to offer greater clarity on how the alliance should react to major cyber attacks — a matter of growing concern amid hacks targeting the U.S. government and businesses around the globe by Russia-based hackers.

Beyond extending the potential use of the Article 5 mutual defense clause to space, the leaders also broadened the definition of what might constitute such an attack in cyberspace, in a warning to any adversary that might use constant low-level attacks as a tactic.

The organization declared in 2014 that a cyber attack could be met by a collective response by all 30 member countries, but on Monday they said that “the impact of significant malicious cumulative cyber activities might, in certain circumstances, be considered as amounting to an armed attack.”

The president started his day meeting with leaders of the Baltic states on NATO's eastern flank as well as separate meetings with leaders of Poland and Romania to discuss the threat posed by Russia and the recent air piracy in Belarus, according to the White House.

Biden's itinerary in Europe has been shaped so that he would first gather with G-7 leaders and then with NATO allies in Brussels before his much-anticipated meeting with Putin in Geneva on Wednesday.

Biden was meeting on Monday evening with Turkey's president, Erdogan, on the summit sidelines.

Biden has known Erdogan for years but their relationship has frequently been contentious. Biden, during his campaign, drew ire from Turkish officials after he described Erdogan as an “autocrat." In April, Biden infuriated Ankara by declaring that the Ottoman-era mass killing and deportations of Armenians was “genocide" — a term that U.S. presidents have avoided using.