SHANGHAI (Reuters) - China’s defense ministry has called on armed groups in northern Myanmar to show restraint and declare an immediate ceasefire after conflicts in the region killed three Chinese citizens.

Three rockets and some stray bullets have also landed in Chinese territory as a result of the fighting, the Ministry of Defence said in a statement on its official Weibo social media account late on Friday.

The ministry said it was paying close attention to the matter and had strengthened patrols and security measures along the China-Myanmar border.

“The Chinese military will continue to strengthen border controls and adopt necessary measures to resolutely safeguard national sovereignty, the stability of the border and the safety of citizens and property,” the statement said.

Tensions in northern Myanmar, which borders southwest China’s Yunnan province, have escalated in the past month, with local ethnic groups demanding greater autonomy in the region, which is an important foreign trade hub for Myanmar.

A Myanmar government spokesman said last Saturday that ethnic insurgents had killed 19 people, including four members of the security forces, in an attack near the main border gate with China.