BEIJING (NYTIMES) - After US President Donald Trump pilloried China in 48 tweeted words, accusing it of failing to tame its neighbour and longtime ally North Korea, Beijing issued its own rebuke to Mr Trump - in a cutting editorial of 1,000 Chinese characters from Xinhua, the official news agency.

"Trump is quite a personality, and he likes to tweet," said the Xinhua response issued late on Monday (July 31) and widely displayed on Chinese news websites. "But emotional venting cannot become a guiding policy for solving the nuclear issue on the peninsula," it said, referring to the divided Korean Peninsula.

The United States, it added, "must not continue spurning responsibility" for the volatile standoff with North Korea, "and even less should it stab China in the back".

The unusually personal nature of the editorial, together with comments delivered earlier that day by China's ambassador to the United Nations in New York, show that North Korea is becoming the main dispute threatening to tear at Mr Trump's initially friendly relationship with his Chinese counterpart, Mr Xi Jinping.

"I am very disappointed in China," Mr Trump declared on Twitter on Sunday, after North Korea tested an intercontinental ballistic missile (ICBM) in defiance of UN sanctions.

Despite China's big trade surplus with the US, he continued in a second tweet, saying, 'they do NOTHING for us with North Korea, just talk".

China's rebuke to Mr Trump did not use exclamation marks. But the Xinhua editorial broke with Beijing's usual public reticence when Mr Trump has taken China to task over trade imbalances, territorial disputes in the South China Sea, Taiwan and other sources of tension.

"Taking out this outrage on China is clearly finding the wrong target," it said, warning such broadsides could be dangerous. "What the peninsula needs is immediately stamping out the fire, not adding kindling or, even worse, pouring oil on the flames," Xinhua said.

The tensions could, it added, "evolve into a localised conflict, or even the outbreak of war, with unthinkable repercussions".

Chinese diplomats and the state news media have consistently argued that Washington and its allies should not rely so much on China to defuse tensions created by North Korea's growing nuclear weapons and missile capabilities.

Last Friday, North Korea tested a ballistic missile that experts have said could have the range to hit California.

US secretary of state Rex Tillerson has turned up pressure on China to help isolate and cajole North Korea. "China and Russia bear unique and special responsibility for this growing threat to regional and global stability," he said in a statement after the launch last Friday.

But the Chinese government argues that North Korea would not back down and return to negotiations over its weapons programmes unless the US and its northeast Asian allies, South Korea and Japan, take conciliatory steps.

In particular, China has proposed that North Korea freeze its nuclear and missile programmes in exchange for a halt to major military exercises by American and South Korean forces on the Korean Peninsula and off its coast.

As the tensions with North Korea have escalated, Mr Trump has often treated Mr Xi in public as a friend who was valiantly, though unsuccessfully, trying to bring North Korea around. "At least I know China tried!" Mr Trump said on Twitter in June.

Now that friendly facade appears to be cracking. But Mr Trump also has a long record of harsh criticisms of China, stretching back to his election campaign and much earlier. "China controls North Korea," he said in 2013. "They are using the Norks to taunt us," he said, using slang for North Koreans.

The Chinese ambassador to the United Nations, Mr Liu Jieyi, said on Monday it was up to the US and North Korea to find a solution to the current standoff, not China.

"People talk about China a lot," he said at a news conference to mark the end of China's July term in the rotating presidency of the UN Security Council. "If the two principal parties refuse to move towards what is required by the Security Council resolutions - de-escalation of tension, negotiations to achieve denuclearisation and peace and stability and also resume dialogue - then no matter how capable China is, China's efforts will not yield practical results because it depends on the two principal parties."

He said that China had upheld UN sanctions against North Korea, while Pyongyang and Washington were heightening tensions by carrying out missile tests and the American side was raising the prospect of new, unilateral sanctions and even the potential for military strikes.

"Instead of de-escalating tension we see of course further testing that we oppose and we also see language and action from elsewhere that heightens tension, talking about 'all options on the table'," he said.

Mr Liu also criticised the US' deployment of the Terminal High Altitude Area Defence (Thaad) anti-missile system in South Korea, which China opposes. He reiterated China's support for a proposal to freeze North Korea's nuclear and missile tests in exchange for the US and South Korea halting large-scale military exercises on the Korean Peninsula.