BEIJING - China's armed forces have moved into new positions along the country's border with North Korea, charged with defending an 870-mile frontier that is often violated by hungry North Korean refugees.
Chinese Foreign Ministry officials confirmed in a statement issued yesterday afternoon that troops from the People's Liberation Army had replaced police along the border, though they did not confirm Hong Kong news reports that the move involved up to 150,000 soldiers.
The move marks a subtle but significant change in relations between the two Communist states, which fought together against the United States in the Korean War and still have a mutual defense treaty.
While Chinese officials described the new border arrangements as a routine adjustment, it comes at a time when Beijing has exerted fresh pressure on North Korea to abandon its nuclear weapons program.
China is the main sponsor of multilateral negotiations involving North Korea, the United States and three other countries aimed at reaching a negotiated settlement to the Korean arms standoff.
The dispatch of army troops also suggests that China could be preparing for the possibility of conflict in the region, though analysts said they considered it highly unlikely that China intends to threaten Pyongyang militarily.
"I think this shows that China is getting more concerned about the overall state of affairs in North Korea and the refugee problem in particular," said Ma Dingsheng, a Chinese military analyst in Hong Kong. "But we are not seeing the kind of deployment you would see if China were contemplating military action."
He said the border troops were the type that guard China's boundaries in other sensitive areas, like the restive Western region of Xinjiang, and were not equipped with tanks or artillery.
The Korean border has been a source of consternation for China in recent years, as North Korean refugees have slipped over in increasing numbers to escape poverty, famine and political repression. Groups devoted to helping the refugees say up to 300,000 North Koreans live in northeastern China, often in constant fear of being captured and repatriated by Chinese police.
The flow of refugees reaches its peak in the winter months, when the Yalu River freezes and people can walk across the loosely patrolled region with little difficulty.
The Bush administration has pressed China to allow more North Koreans to cross the border as a way of pressuring the regime of Kim Jong Il in Pyongyang or even causing it to collapse. But Beijing has resisted those entreaties, and the deployment of troops suggests that it does not plan to relax its stance soon.
Though many North Koreans live and work in China unofficially, Beijing often rounds up refugees and sends them back to North Korea without following United Nations guidelines on assessing whether they fled for political or economic reasons. By many accounts, North Korean authorities severely punish those refugees when they return.
The Foreign Ministry statement said border patrol duties had been assigned to the army, replacing the police. Analysts said the troops would be taking over from the People's Armed Police, a quasi-military unit that performs border duties in some areas.
The statement said a similar adjustment had been made on part of China's border with Myanmar. It did not give a reason for the change in either location.
"It is a normal adjustment carried out after many years of preparation by the relevant parties," the statement said.
Chinese troop movements near North Korea and Myanmar have attracted attention in recent weeks. Several Hong Kong newspapers have reported that as many as 150,000 troops have been assigned to tighten security along the Korean border, equaling the number of soldiers that the United States has stationed in Iraq, but the estimates are unconfirmed.