Chinese authorities are denying a story reported by Reuters, saying that North Korean officials have given Chinese officials advanced notice of its nuclear test plans, and Chinese representatives have called for peace on the Korean Peninsula.

North Korea conducted its third nuclear test last Tuesday. Reuters last Friday cited a source “who has direct access to the top levels of government in both Beijing and Pyongyang” as saying that China has known that North Korea is prepared to stage one or even two more nuclear tests this year in an effort to force the U.S. into diplomatic talks.

"It's all ready. A fourth and fifth nuclear test and a rocket launch could be conducted soon, possibly this year," the source was quoted as saying, adding that the fourth nuclear test would be much larger than the third, at an equivalent of 10 kilotons of TNT.

“Further tests could also be accompanied this year by another rocket launch,” Reuters said.

But Hong Lei, spokesman from the foreign ministry, said he did not know where the Reuters report came from.

"The situation on the peninsula is currently sensitive and complicated,” said Hong. “We appeal for all relevant parties to remain calm and not to take actions that may worsen the situation."

North Korea’s nuclear test has drawn global condemnation including from China. It firmly opposed to the nuclear test, arguing that North Korea was “in disregard of the common opposition of the international community.” Chinese Foreign Minister Yang Jiechi summoned North Korean ambassador to China Ji Jae Ryong after the nuclear test.

Wang Junsheng, a researcher on Korean Peninsular issues with the Chinese Academy of Social Sciences, said he didn’t think China's policy toward North Korea has failed, the official Global Times reported.

“The essence of the nuclear issue is the bilateral interaction between Pyongyang and Washington. China, as a coordinator, shouldn't be singled out to blame for downturns in this complicated matter," Wang was quoted by the paper as saying.

Wang said China this time is quite likely to unleash severe sanctions against North Korea, the paper said.

But Zhang Jian, a researcher at the Department for Asia-Pacific Security and Cooperation under the China Institute of International Studies, believes that the Chinese leadership is divided on how to tackle this hot potato, according to the paper.

"China's North Korea policies are at a crossroad. The North's nuclear test could be a good reason for Chinese decision-makers to alter their approaches to North Korea, but China will risk becoming the enemy of its unpredictable neighbor," Zhang was quoted as saying.

U.S. State Department spokeswoman Victoria Nuland has urged North Korea to "refrain from additional provocative actions that would violate its international obligations" under three different sets of U.N. Security Council resolutions that prohibit nuclear and missile tests, according to Reuters.

European Union governments agreed on Monday to tighten sanctions against North Korea. The sanctions expand those approved by the UN Security Council in January, adding measures preventing trading in North Korean government bonds, gold, precious metals, and diamonds, EU diplomats said.