China-US row over North Korea as tensions rise
China has hit back at US comments criticising Beijing for not reining in its North Korean ally, saying military threats cannot resolve tensions on the Korean peninsula.
Earlier, top US military official Adm Mike Mullen said China was "enabling" North Korea's "reckless behaviour".
Meanwhile, China's top diplomat has met North Korean leader Kim Jong-il in Pyongyang, amid rising tensions.
State media said they "reached a consensus", but gave no details.
The US has been putting pressure on China to intervene after North Korea shelled the South Korean island of Yeonpyeong, near a disputed sea border, killing four people.
South Korea threatened to mount air strikes on the North if it carried out further attacks.'Volatility'
"I actually believe that because these provocations continue, and seemingly at a more frequent interval, that the danger is going up and that steps must be taken to ensure that they stop," said Adm Mullen at a news conference in Tokyo.
"Much of that volatility is owed to the reckless behaviour of the North Korean regime, enabled by their friends in China," he said.
The visit to North Korea by Dai Bingguo, one of China's top foreign policy officials, shows Beijing is keen to reduce tension on the Korean Peninsula.
It certainly needs to do something, because it is coming under increasing pressure to rein in North Korea.
China was previously praised for persuading the North to join the six-party talks aimed at ending Pyongyang's nuclear programmes.
It looked like the country that could broker a deal.
But the talks have stalled, tension has risen and China now looks as though it has little control over a country that it props up with aid and trade.
Beijing has tried to maintain a neutral position, following the shelling of a South Korean island by the North two weeks ago.
It has not publicly blamed Pyongyang for the attack.
But in private Mr Dai will probably have had some tough words for the North Korean leader Kim Jong-il.
"There is too much at stake for this sort of myopia."
Chinese foreign ministry spokeswoman Jiang Yu told a news conference that she questioned what Adm Mullen had done for "peace and stability in the region".
She called his remarks on China's support for North Korea an "accusation".
A senior team of US diplomats is to visit Beijing next week for further talks about the tensions sparked by the shelling.
China, which supplies food and fuel to North Korea, has so far refused to condemn the attack on Yeonpyeong, the first attack of its kind on South Korean civilians since the Korean War ended in a ceasefire in 1953.
China fought on North Korea's side during the war.
Adm Mullen also called on Japan, the US and South Korea to stand together against North Korea.
"I do have a real sense of urgency about addressing the potential in terms of the Korean peninsula that is much better addressed with all of us together, in terms of showing strength and getting to a point where we can deter North Korean behaviour," he said.
Both Japan and South Korea have carried out joint military exercises with the US in the past few weeks.
China has criticised those exercises as an attempt at US containment in an area Beijing sees as its own responsibility.
North Korea: Timeline 2010
26 March: South Korean warship, Cheonan, sinks, killing 46 sailors
20 May: Panel says a North Korean torpedo sank the ship; Pyongyang denies involvement
July-September: South Korea and US hold military exercises; US places more sanctions on Pyongyang
29 September: North holds rare party congress seen as part of father-to-son succession move
29 October: Troops from North and South Korea exchange fire across the land border
12 November: North Korea shows US scientist new - undeclared - uranium enrichment facility
23 November: North shells island of Yeonpyeong, killing at least four South Koreans
27 Nov-1 Dec: South Korea and US hold joint military drills
6-12 Dec: South Korea stages live-fire military exercises
Adm Mullen said South Korea needed to respond to moves by the North with restraint.'Mocked'
North Korea has been defending its shelling of Yeonpyeong as a response to extensive live-firing from the South.
It accused Seoul and Washington of "persistently escalating tension", adding that South Korea had "persistently mocked at the (North's) sincere efforts to improve the inter-Korean relations and turned away their faces from them".
South Korea "fired as many as thousands of shells into the territorial waters of the DPRK (North Korea) side", the state news agency quoted the Secretariat of the Committee for the Peaceful Reunification of Korea report as saying.
"This reckless act was obviously a deliberate provocation to prompt the DPRK to take a military counter-action," it said.
As the latest US-South Korean talks were being held, North Korea conducted military drills in the area.
Tensions on the Korean peninsula have been extremely high since North Korea's 23 November shelling of Yeonpyeong, a small South Korean island close to the disputed western sea border.