China has blocked UN Security Council condemnation of North Korea over its artillery attack on the rival South and its new nuclear activities, diplomats said Tuesday.

The Security Council may now let North Korea's deadly assault last week and the announcement of its new uranium enrichment plant pass without any response because China removed key words from proposed statements, envoys said.

Britain, France and the United States -- backed by South Korea and Japan -- had wanted council statements that specifically condemned the communist North and said it had breached UN Security Council resolutions, diplomats said.

China refused to accept any statement that blamed North Korea or said it had violated any resolution, they added.

China is one of the five permanent members of the Security Council which can veto any resolution. It is also North Korea's closest international ally and has only reluctantly agreed to sanctions against the Pyongyang regime over its nuclear weapons program.

With tensions spiraling on the inter-Korean frontier, the Security Council had held daily contacts on North Korea since the November 22 attack on Yeonpyeong island in which two South Korean marines and two civilians were killed. None were held Tuesday because of the deadlock.

"There were no talks -- neither formal nor informal -- and nothing else is planned," said one diplomat, speaking on condition of anonymity.

"Against the wishes of the vast majority of the Security Council members, China is blocking any action on the uranium enrichment plant and there is not much hope of any talk about the attack," said a second diplomat.

"It says it is unacceptable to condemn' or even express concern' over North Korea. Council talks have come to a standstill.

"It is now very likely that the Security Council will do nothing about North Korea," the diplomat added.

A Chinese diplomat told AFP that "more consultations are needed" on the Security Council action, but would not confirm that China had objected to tough language against North Korea.

After the sinking of a South Korean corvette, the Cheonam, in March this year it took four months to pass a resolution which diplomats said was weakened at China's demand.

Japan is a current member of the Security Council but South Korea has been closely involved in talks on the action.

South Korea has not yet asked for a Security Council meeting on the Yeonpyeong attack and diplomats said it probably would not do so now because of China's action.

There has been international condemnation of the North's shelling of the island of Yeonpyeong last week.

Fears about tensions on the Korean peninsula have been heightened by North Korea's boasting of its new uranium enrichment plant.

The United States and other western nations say that North Korea's new plant is a contravention of Security Council resolutions passed after the North's nuclear tests in 2006 and 2009.

The United States on Monday called for tighter enforcement of the weapons and financial sanctions and travel ban on individuals linked to the North's nuclear arms program.

China has called for talks with North and South Korea, the United States, Russia and Japan on the North Korean crisis. Japan and the United States have rejected the move because of the North's attitude.

The US administration said Tuesday that China had an "obligation" to press North Korea but expected progress in coming days in diplomatic efforts to ease tensions.