While Beijing has likely been deeply angered by North Korea's nuclear test earlier this week, the ruling Chinese Communist Party has only limited options in dealing with its troublesome neighbor, analysts said.
Beijing reacted to Pyongyang's claim it had detonated a hydrogen bomb by restating its now-familiar line, that it "firmly opposes" North Korean leader Kim Jung Un's nuclear weapons program, amid a wider chorus of global condemnation.
Beijing also summoned North Korean top diplomat in Beijing, to whom foreign ministry officials "further elaborated" China's attitude to the tests, a spokeswoman said on Thursday.
"The test is against the normal development of China-DPRK relations," foreign ministry spokeswoman Hua Chunying told journalists, saying that China would continue to work against nuclearization of the Korean peninsula through the U.N. Security Council.
She called for the resumption of six-party talks between China, North and South Korea, Japan, Russia and the United States on Pyongyang's nuclear program.
'Rock and hard place'
But analysts say there is little that North Korea's 'big brother' can do to influence the isolated state in the wake of its latest provocation.
While China is investigating the exact nature of the test, which rocked areas of northeastern China with earthquake-like tremors, including its impact on the safety of its residents near the North Korean border, analysts said Kim is likely impervious to the concerns of his larger neighbor.
According to Ran Bogong, a retired former politics professor at Toledo University, said the test has left China's leaders caught between a rock and a hard place.
"Even if China steps up pressure on North Korea, this won't necessarily be effective," Ran said. "If it doesn't put pressure on North Korea, it will itself come under huge pressure from the international community."
"At the same time, Beijing doesn't want to see North Korea develop its nuclear weapons either, so the current situation has left China stuck between a rock and a hard place," he said.
Yang Liyu, retired professor of East Asian Studies at Seton Hall University in New Jersey, agreed, saying Beijing lacks any real influence over Kim Jung Un, whose mind is on other things.
"Kim Jung Un is deliberately provoking China right now, while he has at the same time been showing goodwill towards Russia," Yang said. "It seems he is trying to draw Russia into conflict with China."
"That's why I don't think China can do anything about North Korea any more," he said.
Beijing's claim that it knew nothing of the test before it was announced on the official North Korean newswire KCNA is probably true, analysts said. China got advance notice of the North's previous nuclear tests in 2006, 2009 and 2013.
"They didn't inform any countries ... of the test before it went ahead," Terence Yeung, of Hong Kong Baptist University's department of government and international studies told RFA.
Kim focused inward
He said the test has boosted tensions in northeast Asia, a matter of concern for all North Korea's neighbors.
"The whole situation in northeast Asia is bound up with the question of North Korea," Yeung said. "Of course this is going to have an impact."
But Yeung said he didn't foresee any major changes in the current situation.
"Apart from some saber-rattling by North Korea, I don't foresee any major changes in the situation in the region in the long term," he said.
And Hong Kong current affairs commentator Lau Lan-chung said Kim is unlikely to be open to any form of external influence, as he is engaged in an internal political struggle to consolidate his power.
"Kim Jung Un's mourning period [for his father, late supreme leader Kim Jong Il] has passed, and now he is consolidating his grip on power for real," Lau said.
"He has to have some achievements to show for it, so he conducts a nuclear test," he said, adding that the North Korean Workers' Party will hold its national party congress in May or June.
"He has to build up his accomplishments before that time, so as to consolidate his position at the helm of North Korea," Lau said.
Western analysts recognize that there are limitations to Chinese influence, as well as fear in Beijing that pushing Pyongyang too hard would bring down the regime and flood northeastern China with refugees.
But critics say China's compliance with the series of UN Security Council sanctions passed with Chinese support is spotty at best and that Beijing has not really applied all the pressure it can bring to bear as the chief source of North Korea's trade, aid and food.
Reported by Lin Ping for RFA's Mandarin Service, and by Wen Yuqing for the Cantonese Service. Translated and written in English by Luisetta Mudie.