Train spotting: North Korean leader Kim Jong Un and officials visit a railway station.

Train spotting: North Korean leader Kim Jong Un and officials visit a railway station. Photo: Reuters

Seoul, South Korea: The execution of the uncle of North Korea's leader, Kim Jong Un, had its roots in a firefight along the country's southwestern coast in September over who would profit from North Korea's most lucrative exports - clams, crabs and coal - according to accounts that are being pieced together by South Korean and US officials.

North Korean military forces were deployed to retake control of one of the sources of those exports, the seafood farms that Jang Song Thaek, the uncle of the country's untested, 30-year-old leader, had seized from the military. In the battle for control of the farms, the emaciated, poorly trained North Korean forces "were beaten - very badly - by Uncle Jang's loyalists," according to one official.

The rout of his forces appears to have been the final straw for Kim, who saw his 67-year-old uncle as a threat to his authority over the military and, just as important, to his own family's dwindling sources of revenue. Eventually, at Kim's order, the North Korean military came back with a larger force and prevailed. Soon, Jang's two top lieutenants were executed.

Final humiliation: Jang Song Thaek, with his hands tied with a rope, is dragged into court before he was executed.

Final humiliation: Jang Song Thaek, with his hands tied with a rope, is dragged into court before he was executed. Photo: Reuters

The two men died in front of a firing squad. But instead of rifles, the squad used anti-aircraft machine guns, a form of execution that according to the Chosun Ilbo, one of South Korea's largest newspapers, was similar to one used against some North Korean artists in August. Days later, Jang himself was publicly denounced, tried and executed, by more traditional means.

Given the opaqueness of North Korea's inner circle, many details of the struggle between Kim and his uncle remain murky. But what is known suggests that while Kim has consolidated control and eliminated a potential rival, it has been at a huge cost: The open warfare between the two factions has revealed huge fracture inside the country's elite over who pockets the foreign currency - mostly Chinese yuan - the country earns from the few non-nuclear exports its trading partners desire.

Only a few months ago Jang was believed to be the second most powerful man in North Korea. In fact, US intelligence agencies had reported to the White House and the State Department in late 2011 that he could well be running the country behind the scenes - and might edge out his inexperienced nephew for control. In part that was based on his deep relationship with top officials in China, as well as his extensive business connections there.

His highly unusual public humiliation and execution on December 12 set off widespread speculation about the possibility of a power struggle within the secretive regime. But in recent days a more complex, nuanced story has emerged.

During a closed-door meeting Monday of the South Korean National Assembly's intelligence committee, Nam Jae-joon, director of the National Intelligence Service, disputed Pyongyang's assertion that Jang had tried to usurp his nephew's power. Rather, he said, Jang and his associates had provoked the enmity of rivals within the North's elite by dominating lucrative business deals, starting with the coal badly needed by China, the North's main trading partner.

"There had been friction building up among the agencies of power in North Korea over privileges and over the abuse of power by Jang Song Thaek and his associates," Nam was quoted as saying. Nam's comments were relayed to the news media by Jeong Cheong-rae and Cho Won-jin, two members of parliament designated as spokesmen for the parliamentary committee.

In interviews, officials have said that the friction described in general terms to the South Korean parliament played out in a violent confrontation in late September or early October, just north of the border between North and South Korea.

There, the North nurtures its clam and crab farms, delicacies that are also highly valued by the Chinese. For years the profits from those fish farming operations, along with the output from munitions factories and trading companies, went directly to the North Korean military, helping it feed its troops, and enabling its top officers to send cash gifts to the Kim family.

South Korea was a major market for the North's mushrooms, clams, crabs, abalones and sea cucumbers until South Korea cut off trade with the North after the sinking of a South Korean navy ship in 2010, forcing the North Korean military to rely on the Chinese market.

But when Kim succeeded his late father two years ago, he took away some of the military's fishing and trading rights and handed them to his Cabinet, which he designated as the main agency to revive one of the world's most sanctioned, moribund economies. Jang was believed to have been a leading proponent of curtailing the military's economic power.

Jang appears to have consolidated many of those trading rights under his own control - meaning that profits from the coal, crabs and clams went into his accounts, or those of state institutions under his control, including the administrative department of the ruling Workers' Party of Korea, which he headed.

But earlier this year, the long-brewing tensions that arrangement created broke into the open. Radio Free Asia, in a report last week that cited anonymous North Korean officials, reported that Kim Jong Un saw North Korean soldiers malnourished during his recent visits to islands near the disputed western sea border with South Korea. They say he ordered Jang to hand over the operation of a nearby seafood farm back to the military.

According to accounts put together by South Korean and US officials, Jang resisted. When a company of about 150 North Korean soldiers showed up at the farm, Jang's loyalists refused to hand over the operation, insisting that Jang himself would have to approve. The confrontation escalated into a gun battle, and Radio Free Asia reports that two soldiers were killed and that the army backed off. Officials say the exact number of casualties are unknown, but they have received similar accounts.

It is hard to know exactly how large a role the incident played in Jang's downfall - there is more money in coal than seafood - but Kim was reportedly enraged when he heard of the clash. Nam said that by mid-November his agents were already reporting that Jang had been detained. The December 12 verdict noted that Jang "instructed his stooges to sell coal and other precious underground resources at random."

Nam said the fact that such behind-the-scenes tensions had so spun out of control that he had to order his own uncle's execution raised questions about the regime's internal unity.

"The fissure within the regime could accelerate if it further loses popular support," the members of parliament quoted Nam as saying.

Jang was the husband of Kim Kyong Hui, the only sister of Kim's late father, the longtime leader Kim Jong Il. Nam told the committee on Monday that Kim's aunt had retained her position in the North Korean hierarchy, even while the purge of Jang's other associates continued. But he denied news reports in South Korea and Japan that some of Jang's associates were seeking political asylum in Seoul and Beijing.

Nam pointed to Vice Marshal Choe Ryong Hae, the top political officer in the North Korean People's Army, and Kim Won Hong, the head of the North's secret police and its intelligence chief, as the regime's new rising figures since Jang's execution, the two lawmakers said.

The New York Times