BEIJING, March 31 (Reuters) - Spanish Prime Minister Pedro Sanchez encouraged Chinese President Xi Jinping on Friday to talk to the Ukrainian leadership and learn first-hand about Kyiv's peace formula to help bring an end to Russia's invasion.

Sanchez told a news conference in Beijing he had informed Xi, who visited Moscow on March 20-21, that Spain supported the proposals made by Ukrainian President Volodymyr Zelenskiy. These include a demand to restore Ukraine's territory to the status quo before Russia's 2014 annexation of Crimea.

"I believe it's a plan that lays the foundations for a durable peace in Ukraine and is perfectly aligned with the United Nations charter and its principles, which have been violated by (Russian President Vladimir) Putin with his invasion," he said.

"I transmitted our concern over the illegal invasion of Ukraine," Sanchez said, adding that he encouraged Xi to talk to President Zelenskiy in order to get to know first-hand Kyiv's peace plan.

Last month, Beijing put forward its own 12-point position paper on a political solution to the war in Ukraine, which included a comprehensive ceasefire in the conflict.

However, the paper also raised eyebrows among some EU officials in China for not stating that the aggressor in the conflict was Russia.

Sanchez on Thursday praised two aspects of China's position paper - "its complete and categorical rejection of not only the use but even the threat to use nuclear weapons" and its respect for territorial integrity.

Sanchez declined to say what Xi had said about the issue.

Russia has said Ukraine must accept its loss of Crimea and four other regions in the south and east of the country.

According to a readout of the meeting from Chinese state broadcaster CCTV, Xi called for an end to a "Cold War mentality" and to the pressure of "extreme" sanctions, though he did not name Russia.

"We hope that all parties concerned will build a balanced, effective and sustainable European security architecture through dialogue and consultation," CCTV quoted Xi as saying.

Spain, a NATO member whose foreign and security policy is closely aligned with that of the United States, is a staunch ally of Ukraine. In July it assumes the rotating presidency of the European Union's Council, which groups the bloc's 27 national governments.