The European Union and China are to celebrate the 50th anniversary of the establishment of bilateral diplomatic relations in Beijing, as many contentious issues dampen the festive mood.

European Commission President Ursula von der Leyen and European Council President António Costa are to meet Chinese President Xi Jinping and Prime Minister Li Qiang on Thursday to discuss trade, the war in Ukraine and climate change.

China and the EU are each other’s second most important trading partners, but the current commercial relationship is “unsustainable” for the bloc, an EU official said ahead of the meeting.

Last year the EU’s trade deficit with Beijing grew to more than €300 billion ($352 billion).

The imbalances are growing as China exports large quantities to Europe but imports very little and limits access to the Chinese market for European companies.

The EU increased tariffs on electric vehicles made in China last year, claiming large-scale subsidies give Chinese manufacturers an unfair advantage.

Brussels however is hoping to avoid escalating trade tensions as its remains dependent on China in other areas. EU countries heavily rely on Chinese imports of rare earth elements.

In addition, China’s support for Russia in its war against Ukraine has long been of concern to the EU. According to EU officials, Costa and von der Leyen plan to insist on an unconditional ceasefire in Ukraine and an interruption of direct or indirect aid from China to Russia.

Despite the tensions, the EU hopes for cooperation with China on tackling climate change and cutting greenhouse gas emissions.