Officials in Ruili, in Southwest China's Yunnan province, launched a border security emergency plan after an attack by an insurgent group in bordering Myanmar killed at least 19 people.
The attack began early Saturday and lasted about three hours, beginning on the outskirts of the town of Muse in Shan State, said Sai Kyaw Thein, a member of Parliament from Muse, the Sydney Morning Herald reported.
Fifteen civilians, including two women, were killed, and 20 were wounded, according to a Myanmar government spokesman.
The Ruili government began the emergency plan to protect civilians and property and will help civilians in border areas to resettle. There were no reports of casualties in China.
The Ta'ang National Liberation Army (TNLA), made up of fighters from the Ta'ang or Palaung ethnic group, said the group had attacked a casino run by militiamen and a Myanmar army post on the outskirts of Muse, a few hundred meters from a river that separates Myanmar's northern Shan state and Yunnan province.
China's embassy in Myanmar said that the conflict had sent stray bullets into China, along with an unidentified number of people seeking refuge.
"China's embassy in Myanmar condemns this violent incident, and feels pained for the relevant innocent people who were harmed," the embassy said in a statement, adding that it had made "solemn representations" to Myanmar's government.
China called for all parties to "exercise restraint", implement a ceasefire and prevent the situation from escalating.
Violence on the Myanmar side of the border has in recent years sent thousands fleeing through the rugged mountain terrain into China, where the Chinese government at times has set up relief camps.