BEIJING • Chinese President Xi Jinping appears to be back in US President Donald Trump's good graces - at least for now.

North Korea's second intercontinental ballistic missile test on July 28 led Mr Trump to lash out at China on Twitter, and then his administration was reported to be getting ready to take steps that could lead to a trade war.

That all changed with a breakthrough at the United Nations last Saturday. After a month of talks, the US and China agreed on sanctions that would cut North Korea's exports by a third, punish some of its biggest companies and cap the number of its citizens working in other countries at current levels.

"It is enough to give the administration some new hope that it can work with China on North Korea and trade," said Mr Dennis Wilder, a former senior director for Asia at the National Security Council. The move would "almost certainly" stop the US from imposing secondary sanctions on China, and may delay a probe into intellectual property theft, he added.

Still, while Chinese Foreign Minister Wang Yi expressed confidence on Sunday that the sanctions would bring the North's leader Kim Jong Un back to the negotiating table, many North Korea watchers remain sceptical.

"If the past decade has told us anything, it is that sanctions and condemnation alone won't do it," said Mr Hans Kristensen, director of the Nuclear Information Project at the Federation of American Scientists. "They must be paired with incentives that make it attractive for North Korea to change."

China - North Korea's main ally and trading partner - has been regularly accused of failing to fully implement previous UN resolutions. China sees the collapse of Mr Kim's regime as a greater strategic threat that could lead to a refugee crisis and US troops on its border.

While last Saturday's sanctions are significant, some analysts do not see them as effective.

"The problem with North Korea is it is all too small," said associate professor of Chinese studies John Delury of Yonsei University in Seoul, referring to the economic stakes. "It is trying to use a method that would work after we brought the North Korean economy into the region, into the world. But it is not effective at this stage."

"The Trump administration has made it explicit that there is a constant trade-off between trade issues and North Korea," he added. "It would appear President Trump is happy with Xi now, but it wouldn't be surprising in a matter of weeks for a tweet to say now he is disappointed again."

BLOOMBERG