North Korea has issued a rare direct criticism of China through a commentary saying its "reckless remarks" on Pyongyang's nuclear programme are testing its patience and could trigger unspecified "grave" consequences.
China, North Korea's largest trading partner and main benefactor, has been urging the North to stop nuclear and missile activities amid US pressure to use its leverage to resolve the nuclear stand-off.
The commentary, released by the state-run Korean Central News Agency, says "a string of absurd and reckless remarks are now heard from China every day, only to render the present bad situation tenser".
It is unusual for the North to directly criticise Beijing.
Previously it has couched such criticism by referring to China only as "a neighbouring country".
The article cited commentaries by Chinese state media that it said shifted the blame for deteriorating bilateral relations on to the North and raised "lame excuses for the base acts of dancing to the tune of the US".
"China should no longer try to test the limits of the DPRK's patience," the North Korean commentary said, using its official name, the Democratic People's Republic of Korea.
"China had better ponder over the grave consequences to be entailed by its reckless act of chopping down the pillar of the DPRK-China relations."
The article was not attributed to any government agency or official and the writer was identified only as Kim Chol.
Chinese state media has recently unleashed regular and harsh criticisms over the North's actions.
The Global Times, an outspoken nationalist tabloid published by the ruling Communist Party's flagship People's Daily, warned in a Thursday editorial that the North's actions threatened a 1961 treaty of non-aggression between the two countries.
It called on the regime to end its nuclear tests.
"China will not allow its northeastern region to be contaminated by North Korea's nuclear activities," the Global Times declared.
In recent days, the paper also warned that China was able to strike back "at any side that crosses the red line" and would impose an oil embargo against the North in response to any more tests.
The North Korean commentary said it was China that crossed "the red line".
The People's Daily declared on Sunday, and again on Tuesday, that the North's nuclear ambitions "put itself and the whole region into dire peril".