BEIJING — China said todaythat its military has taken over patrolling its frontier with North Korea, but wouldn't disclose why it made the change.
The Foreign Ministry would not confirm reports in Hong Kong media that China moved 150,000 troops to the border to stem crime by North Korean soldiers and to pressure its isolated communist neighbor to halt its nuclear weapons program.
"It is a normal adjustment carried out after many years of preparation by the relevant parties," the Chinese Foreign Ministry said in a brief statement.
It wasn't clear which agency previously patrolled the border, which is off-limits to foreign reporters. But such duties are believed to have been held by the People's Armed Police, a paramilitary force also run by the Defense Ministry.
U.S. and South Korean analysts, who said they couldn't confirm the troop movements, disagreed over whether Beijing would take such a step to pressure its longtime ally.
A U.S. official, speaking on condition of anonymity, said the Chinese have been reorganizing border forces for about a year, replacing border guards with army troops to increase security along its frontier, including the North Korean border, and the move does not appear to be linked to a specific issue.
China fought alongside North Korea in the 1950-53 Korean War and is the isolated North's main aid supplier. But diplomats and scholars say the North has angered China by declaring it had nuclear weapons and resisting U.S. pressure to scrap its weapons programs.
Beijing has tried unsuccessfully to mediate the weapons dispute. A second round of talks in August ended without agreement or a date for more negotiations.
David M. Lampton, director of China studies at the Johns Hopkins School of Advanced International Studies in Washington, said China has been "ratcheting up the pressure" on the North — especially since it said in April that it already had a nuclear weapon.
"I wouldn't be surprised if China" moved troops to the border, Lampton said. "This could be an attempt to show that China won't be intimidated."
But Baek Seung-joo of South Korea's government-run Korea Institute for Defense Analysis was skeptical about possible Chinese attempts at military pressure.
"Considering the relations between China and North Korea, it is difficult to imagine that China would use its military as a means to influence North Korea," said Baek, leader of the institute's North Korea research team.
Chinese government spokesmen in the border cities of Yanji, Tumen and Hunchun said they had no information about the change in patrols along the 870-mile border or any troop deployments.
China has the world's largest military, but it has announced plans to cut back its forces to about 1.5 million troops. The figure of 150,000 troops, reported by the Sing Tao newspaper, would represent a full one-tenth of that force devoted to a small section of border for China, which has frontiers with 14 countries.
Troops also patrol China's borders in the restive western regions of Tibet and Xinjiang.
Sing Tao said the troops also were meant to stem cross-border crime by North Korean soldiers and the flow of refugees fleeing repression and hunger in the North.
China has been frustrated and embarrassed by the refugees, who are believed to number in the tens of thousands. Nearly 200 have been allowed to leave for rival South Korea after seeking asylum in embassies and other foreign offices.
"The Chinese could be hedging against any North Korean attempt to pressure them by having more refugees move into China," Lampton said.
The Foreign Ministry statement said China's army also is taking over border-patrol duties from police on the frontier with Myanmar in the southwest, a major heroin-smuggling area.
The statement gave no reason, but Chinese police in the area say they are outgunned by drug gangs.