Washington has urged Beijing to support a new round of UN sanctions against North Korea after its defiant rocket launch last week, a diplomatic source in Seoul said.

China, North Korea’s main ally, expressed “concern” over Pyongyang’s launch of a long-range rocket that put a satellite into orbit but showed no signs of endorsing tougher measures against the pariah state sought by the UN Security Council.

Beijing, which has veto power in the Security Council, reiterated that any UN response to Pyongyang should be “prudent”.

“The Chinese side repeated its stance that it wants to keep peace and stability on the Korean peninsula,” a diplomatic source said after senior diplomats from South Korea and China met in Beijing on Monday.

Seoul said it was considering imposing separate sanctions against Pyongyang should Beijing fail to cooperate with the international body.

North Korea is already subject to UN sanctions over its previous nuclear and missile tests. Last week’s launch came as a surprising success after a failed attempt in April. US scientists, however, said the orbiting satellite was apparently not functioning and not pointing to Earth as it should.