China will maintain “high-level cooperation” in energy with Saudi Arabia, President Xi Jinping told Crown Prince Mohammed bin Salman on Friday, as the war in Ukraine continued to push up fuel prices.

In a call between the two leaders, Xi said China “prioritises developing relations with Saudi Arabia”.

They also exchanged views on Ukraine, and agreed to deepen cooperation in energy, trade, high technology, transport, and infrastructure, according to a statement from the Chinese foreign ministry.

The two countries would also push to link China’s Belt and Road Initiative with Saudi Arabia’s Vision 2030, and increase cooperation between China and the Gulf Cooperation Council and Arab League, the statement said.

“The overall and strategic importance of the China-Saudi relationship has become greater with the change in the international and regional situations,” Xi was quoted as saying.

Saudi Arabia has long been the biggest oil supplier to China, the world’s largest oil buyer. The Gulf state supplied 17 per cent of China’s total crude oil imports last year, followed by Russia with 15.5 per cent.

Russia temporarily became the monthly top seller in December, only to be overtaken Saudi Arabia in the next two months.

Western sanctions on Russia following its invasion of Ukraine in late February have made buying Russian oil more difficult but China has insisted that oil and gas cooperation with Russia will continue.

This has raised speculation in the market that China will increase its energy imports from Russia and cut imports from Saudi Arabia.

Yin Gang, a Middle East affairs researcher with the Chinese Academy of Social Sciences, said the main point of Xi’s call with Salman was to ease such speculation.

“There’s a need to guarantee that China’s imports from Saudi Arabia will be stable, the commitment is consistent,” Yin said.

“In fact, Saudi Arabia’s oil exports to China are the most stable among our energy import countries.

“For Russia, the capacity to export energy is limited by the capacity of its pipelines. But Saudi Arabia can increase its capacity and be more flexible because it depends on shipping.”

Jonathan Fulton, international relations professor at Zayed University in the United Arab Emirates, said it was likely that both sides had concerns about how the war would affect energy markets.

“With speculation that Beijing will take advantage of Russian vulnerability through sanctions, the Saudis may be concerned that they will lose market share,” he said.

Fulton said the Chinese leaders were probably concerned about energy market instability, especially given the economic difficulties they faced leading up to the Communist Party’s national congress later this year.

“These concerns could be the underlying message of the phone call. At the same time, the wide range of issues discussed shows that the bilateral relationship is more than oil; the two countries have been developing a long-term vision of cooperation,” he said.

During Friday’s call, Salman underlined his country’s “firm support” for China’s policy in Xinjiang and opposition to interference in China’s internal affairs, emphasising the “rights of each country to choose its own political and human rights path”, the Chinese statement said.

Beijing has been accused of human right abuses in Xinjiang in its treatment of millions of ethnic Uygurs and other Muslims, an approach that Beijing defends as deradicalisation.

Salman also said Saudi Arabia supported the “one-China principle”, the statement said.