BEIJING (AFP) - North Korea's sole major ally China urged "all relevant parties" to show restraint today after Pyongyang said it planned to carry out a third nuclear test and more rocket launches aimed at the US.

"All relevant parties should refrain from action that might escalate the situation in the region," foreign ministry spokesman Hong Lei told reporters in Beijing.

China hoped they would "stay calm, be discreet in words and deeds and look at the long term interest and push for the resumption of the six-party talks," he said, referring to long-stalled negotiations over the North's nuclear programme.

The comments came after the North hurled fresh invective at its US-led foes in a statement from its National Defence Commission, without specifying when the atomic test - part of an "upcoming all-out action" - might be carried out.

"We do not hide that the various satellites and long-range rockets we will continue to launch, as well as the high-level nuclear test we will proceed with, are aimed at our arch-enemy the United States," the commission said.

China is the North's leading energy supplier and trade partner, but Beijing backed a UN Security Council resolution this week that condemned Pyongyang's rocket launch last month and imposed fresh sanctions.