US and South Korean troops opened 11 days of war games Monday in the face of North Korean threats to turn Seoul into “a sea of fire” and to start “all-out war.”

Officials dismissed the rhetoric from North Korea as a sign of rising North Korean anger in a familiar cycle of threats. The US command here says the exercises, involving nearly 13,000 US troops and 200,000 Korean civilians mainly conducted on computers, had been in the planning stage for months and were entirely “defensive.”

The real question is the degree to which China will act to discourage a North Korean response akin to what happened last year following similar drills. Though North Korea has repeatedly denied any role, an international investigation blamed it for sinking the South Korea’s Navy corvette the Cheonan nearly a year ago, killing 46 South Korean sailors.

China's concern

China maintains its prime concern on the Korean peninsula is “stability,” but has pointedly refused to support the results of the South Korean investigation with international participation, the Cheonan incident. Last week, it opposed a move in the United Nations to condemn North Korea for construction of a new nuclear reactor capable of enriching uranium for nuclear weapons.

“After the Cheonan incident, we have witnessed a new chapter in the war for the Korean peninsula,” says Koo Kab-woo, professor at the University of North Korean Studies here. “The new situation depends on China. North Korea has to talk to China before doing anything.”

China, says Professor Koo, wields power over North Korea by modulating the flow of food as the North suffers through the coldest winter in many years. “That way China can manipulate the North Korean planning,” he says. With China providing the North with 80 percent of its food and fuel, he notes, Chinese officials “have leverage.”

Defiance

North Korea, however, may still be tempted to defy South Korea, responding not to war games but to the launching over the past week of balloons carrying several hundred thousand propaganda leaflets from the South. The leaflets include detailed reports of protests in the Middle East – a precedent that North Korean leaders clearly do not want their own people to know about.

While there is no way of telling how many have been read, enough of them have fallen into the hands of North Koreans for the government to threaten to fire at launch sites the next time balloons are launched.

Another sign of North Korean concern about the impact of events in the Middle East is a report that authorities have cut off cellphone service between Korean cities except for conversations among high-level officials. More than 300,000 North Koreans now have cellphones provided by the Egyptian firm Orascom Telecom.

“They are afraid news of the democracy movement will spread,” says Ha Tae-keung, president of Open Radio for North Korea, which picks up information from North Korea on cellphone contacts through Chinese networks and broadcasts two hours daily by shortwave into the North.

South Korean officials staunchly deny any direct role in the balloon launches, which they say are the handiwork of nongovernmental organizations, several of them spurred by defectors from North Korea.

“We do not have the legal means to restrict them,” says an official from the South’s Unification Ministry, responsible for dealing with North Korea. The government, he says, has “advised them to cut down their activities, but they continue to send them.”

As for the latest spate of invective from North Korea, Mr. Ha believes the North is still hoping to bring about renewal of six-party talks about its nuclear program. While the North would not give up its nuclear program, he says, North Korean diplomats would then get the chance to bargain for much needed food. Supplies reach their lowest levels in the late spring and early summer before the current year’s crops are harvested.

“These days, North Korea wants to get more food from the rest of the world,” he says. “They want to have rice from the United States” – one of the biggest sources of food aid before South Korea’s conservative President Lee Myung-bak cut off most aid to North Korea three years ago and the US agreed to follow suit.