NATO's chief warned Monday that the Western alliance needs to impose costs on China over support for Russia, while saying that only a regular flow of weapons to Ukraine could end the war.

Secretary General Jens Stoltenberg was paying a visit to Washington to lay the groundwork for the 75th anniversary summit of NATO next month.

The July gathering aims to send a decisive long-term message of support for Ukraine as President Joe Biden faces a tough reelection fight against Donald Trump, a skeptic of Western support for Kyiv.

Speaking ahead of a meeting with Biden, Stoltenberg accused China of worsening the conflict through what US officials say is a major export push to rebuild Russia's defense industry.

President Xi Jinping "has tried to create the impression that he is taking a back seat in this conflict, to avoid sanctions and keep trade flowing," Stoltenberg said at the Wilson Center.

"But the reality is that China is fueling the largest armed conflict in Europe since World War II, and at the same time, it wants to maintain good relations with the West," he said.

"Beijing cannot have it both ways. At some point -- and unless China changes course -- allies need to impose a cost. There should be consequences."

China argues that it is not sending lethal assistance to either side -- unlike the United States and other Western nations.

Beijing steered clear of a weekend summit in Switzerland promoted by Ukrainian President Volodymyr Zelensky that reaffirmed Kyiv's demands for Russia to leave Ukrainian territory for any peace.

Russia has insisted that it is interested in talks, but has demanded Ukrainian forces to withdraw from territory seized by Moscow.

Trump -- who in the past has voiced admiration for Russian President Vladimir Putin -- has boasted that he can quickly end the war, likely by pressing Ukraine to accept demands.

In an unstated effort to "Trump-proof" future efforts, Stoltenberg wants the Washington summit both to put NATO in the lead of coordination on Ukraine and to set up a way for long-term military support.

"The more credible our long-term support, the quicker Moscow will realize it cannot wait us out," he said.

"It may seem like a paradox, but the path to peace is more weapons for Ukraine."

The US Congress in April approved some $60 billion in new military funding for Ukraine but only after months of delay due to political fighting and opposition by some of Trump's Republican allies.