China has given its strong backing to Pyongyang in a move that could alter the power dynamic on the Korean peninsula, but analysts say Beijing should be cautious about using its neighbour as leverage with Washington.

Beijing’s influence on the peninsula was on display last week during President Xi Jinping’s first state visit to Pyongyang, where he said China’s commitment to assist North Korea would not change, and called for dialogue between Pyongyang and Washington.

Analysts said pledges made by Xi during the visit – after talks collapsed in February between North Korean leader Kim Jong-un and US President Donald Trump – were a sign that Beijing and Pyongyang, as well as Moscow, were becoming more aligned against Washington. But the approach, ahead of planned talks between Xi and Trump this week, could backfire on China, they said.

Pyongyang put on a lavish reception for Xi, who also visited a monument commemorating Chinese soldiers who fought on the side of North Korea during the Korean war.

On Saturday, North Korean state media said Xi and Kim had reached consensus on important issues after exchanging views on domestic and international matters of mutual concern.

“The top leaders … expressed their will to carry forward the friendly relations, regardless of the changes in the international situation,” according to the Korean Central News Agency.

Xi told Kim that China was determined to support the country’s new “strategic path”, while Kim said Pyongyang had taken steps towards denuclearisation, but it had not received a “positive response from the relevant party”.

Lim Eul-chul, a North Korea expert at the Institute for Far Eastern Studies at Kyungnam University in Seoul, said the situation was becoming “very complicated”.

“I read China’s vow to North Korea as Beijing’s determination to align with Pyongyang against Washington,” Lim said. “North Korea-China relations have been widely referred to as ‘blood ties’, but in reality this is largely just rhetoric. However, given that Xi explicitly backed the survival of the North Korean regime and displayed its influence over Pyongyang to the international community, [it appears] ties between the two countries have improved at a practical level.”

China has been North Korea’s biggest guarantor of security since the Korean war from 1950 to 1953, and the 1961 Sino-North Korean Mutual Aid and Cooperation Friendship Treaty promises Chinese military intervention if the country is “subjected to armed attack by any state or states”.

Relations had cooled between Pyongyang and Beijing after Kim took power in 2011, with North Korea dismayed by China’s endorsement of sanctions against the regime over its nuclear and missile tests. Pyongyang’s provocations prompted calls among Chinese government advisers and observers for Beijing to move away from such a close bond with its communist neighbour.

But the two countries began edging closer again after Pyongyang started to focus more on developing its economy, demanding United Nations sanctions be lifted. Kim visited Beijing twice ahead of his first meeting with Trump in Singapore, in what was seen as a move to secure backup before the summit, showing China still had leverage over North Korea. Kim has since made two more trips to China and one to Russia, with economic development high on the agenda.

Zhao Tong, a fellow at the Carnegie ­Nuclear Policy Programme at the Carnegie-Tsinghua Centre for Global Policy, said the emphasis on historical bonds and the rapprochement between China, Russia and North Korea would prompt suspicion from the West.

“China and Russia are becoming closer as they share similar views on governance and international relations. China, Russia and North Korea will also edge closer as their ideology is similar – and there will be a backlash from the United States and its allies,” Zhao said.

“Pyongyang will have to manoeuvre between China and the US to survive, and that will inevitably result in a shift in the power dynamic.”

Xi was the first Chinese president to make a full state visit to North Korea, and Beijing appears to be taking a more pragmatic approach to what is now a nuclear-armed state.

Before the trip, Chinese state media said economic cooperation would be on the agenda. But Zhang Liangui, a North Korean affairs expert from the Central Party School in Beijing, noted that this was not emphasised in official reports on the Xi-Kim talks.

“This indicates that China has taken seriously the implementation of United Nations sanctions on North Korea,” he said. “China is unlikely to provide too much economic support to the North.”

He said even though denuclearisation was an area where China and the US could cooperate, Beijing “wouldn’t get any strategic benefit from playing the North Korea card”.

“Both China and the US share a common interest in the North Korea nuclear issue, and it is not in China’s interest for the North to develop nuclear arms,” Zhang said.

Zhao agreed that China was likely to tread carefully with the US when it came to North Korea given their tense relations over trade, technology and security, and said lifting the sanctions would only worsen the situation.

“The US has sufficient tools for a counter-attack on China,” Zhao said. “China still wants to show a cooperative attitude – that it’s willing to help in exchange for more cooperation from the US on other issues.”

But Jin Chang-soo, a senior researcher at South Korean think tank the Sejong Institute, said China may have another goal that would further complicate the power dynamic in the region.

“China’s pledge [to secure the North Korean regime] could mean that it may want to use the denuclearisation issue to achieve the withdrawal of US forces from South Korea,” Jin said.