EU leaders called on China’s President Xi Jinping to pressure Russia into ending its war on Ukraine as they acknowledged that relations between Beijing and Brussels have reached an “inflection point.”

The pointed remarks, which underscored the deep tensions in the EU-China relationship, came at the start of a summit commemorating 50 years of diplomatic relations between the two on Thursday.

European Commission President Ursula von der Leyen and European Council President António Costa traveled to Beijing to meet with China’s Xi — after Xi himself snubbed an invitation to travel to Brussels for the event.

The EU and China “have reached an inflection point” in their relations, von der Leyen told Xi in her opening remarks in Beijing. “As our cooperation has deepened, so have the imbalances.” She added that “it is vital for China and Europe to acknowledge our respective concerns and come forward with real solutions.”

In his opening remarks, Council President Costa also noted the imbalance in economic relations, saying “we need concrete progress on issues related to trade and economy. And we both want our relationship to be balanced, reciprocal and mutually beneficial.”

And he jabbed Beijing over the role it has played in Russia’s full-scale invasion of Ukraine.

“As a permanent member of the United Nations Security Council, we call on China to use its influence on Russia to respect the U.N. Charter and to bring an end to its war of aggression against Ukraine,” Costa said.

The EU last week listed two Chinese banks in its latest sanctions against Russia, leading Beijing to issue “strong dissatisfaction and resolute opposition” at the “egregious” move.

President Xi, in his remarks, agreed that EU-China relations are at a “critical juncture.”

He described China and the EU as “two big guys” on the world stage that must both “make correct strategic choices that meet the expectations of the people and stand the test of history.”

“China and Europe should enhance communication, strengthen mutual trust, and deepen cooperation, providing the world with more stability and certainty,” Xi said.

The EU presidents will hold talks with Xi on Thursday, and will also meet with China’s Premier Li Qiang.