China said Thursday that it had expressed “grave concern” to the Myanmar government after a shell, apparently fired during fighting between Myanmar troops and ethnic rebels, landed in Chinese territory, and a Chinese government spokesman called for an immediate cease-fire.

The Chinese response was unusually strong given the close ties between the two countries in recent years, and it suggested that China was growing increasingly impatient and nervous about the Myanmar government’s campaign against ethnic Kachin rebels.

“China has lodged urgent representation to Myanmar over the incident, to express grave concerns and dissatisfaction,” said Hong Lei, a spokesman for China’s Foreign Ministry, who called for a cease-fire, according to the official Xinhua news agency.

Daw Aung San Suu Kyi, the opposition leader in Myanmar’s Parliament, called for an immediate stop to the fighting. But her comments, reported by the Irrawaddy online news site, were equivocal. She said she could not help more forcefully to resolve the conflict because she was not on the ethics committee.

“That doesn’t mean that I don’t take responsibility for the matter or that I don’t care about it, but different committees should respect each other and not interfere in each other’s work,” she said.

Myanmar’s government has repeatedly said that it wants to negotiate with the Kachin rebels, “We want to reduce our offensive and return to talks,” U Ye Htut, a spokesman for President Thein Sein, said in an interview with The Irrawaddy online news site that was posted on Thursday.

But the military appears to be accelerating its campaign against the Kachin using heavy artillery, attack helicopters and other aircraft to flush out guerrillas from their positions surrounding Laiza, a town along the border with China that is the headquarters of the Kachin Indepedence Army.

Human Rights Watch on Friday called on Myanmar to stop what it described as “indiscriminate” shelling of Laiza, where three civilians were killed earlier this week from what rebels said was an attack by government troops.

Xinhua said the artillery shell was the fourth “bomb” dropped inside China since Dec. 30, when three others landed in Chinese territory.

Bertil Lintner, a specialist on Myanmar’s ethnic groups, said China feared an influx of refugees and further damage to trade along the border. The fighting has disrupted a number of Chinese hydroelectric projects in Myanmar, as well as jade mining.

“They are getting increasingly annoyed with what’s going on at the border,” Mr. Lintner said. “But the Chinese don’t really know what to do. They can’t antagonize the K.I.A.,” he said, referring to the Kachin Independence Army, “and they can’t antagonize the Burmese government either.”

Kachin rebels still control swaths of territory along the border with China, including areas where Chinese companies own plantations.

The Chinese government dealt directly with the Kachin for more than two decades, including the 17-year period when a cease-fire with the government allowed the Kachin to control border trade and maintain a degree of autonomy. The cease-fire collapsed in June 2011.

Link: http://www.nytimes.com/2013/01/18/world/asia/china-objects-after-shell-is-fired-from-myanmar.html?ref=asia&_r=0