The PLA yesterday mobilised troops for a live-fire drill in Yunnan province near the Myanmar border, in a show of determination to uphold the security of the frontier amid escalating tensions in the region. Aviation, artillery, air defence, infantry, missile and radar units took part, according to the People's Liberation Army's Chengdu Military Area Command. Several thousand soldiers, both regular and reserves, from the army, air force and missile units were involved, with warplanes and several hundred heavy artillery vehicles being deployed in mountainous areas, the Chinese military said. Senior Colonel Tang Jibing said the exercise would "test military manoeuvres, reconnaissance, strike power, mobilisation and militia reserve support", state-run Xinhua reported. "Drills are an effective way to enhance joint operations capabilities and are necessary in safeguarding the frontier and protecting people's lives and property," Tang said. The exercise would be conducted in accordance with "training plans" and attack targets would be selected "randomly", said Tang. He did not say when the drill would end. Pictures released online by the Chinese military showed PLA tanks heading to the exercise. The Chengdu command released the coordinates of the area where the exercise is being held. These were near Zhenkang county's Nanzan town, which is close to the Myanmar border. Two Myanmese artillery shells landed in Nanzan on May 14, injuring five people. In March, a Myanmese plane accidentally dropped a bomb on the Chinese side of the border, in Gengma county, killing five people and injuring eight. These incidents prompted protests from Beijing, which warned the Myanmese government against allowing its fight against the rebel Myanmar National Democratic Alliance Army to spill over the border. Foreign Ministry spokeswoman Hua Chunying on Monday said the drills were "a regular activity within the scope of the military's mission". But she also said China hoped "that Myanmar can work with [us] to ensure peace and tranquility in the two countries' border areas". Nearly 90,000 civilians in northeastern Myanmar are thought to have fled the fighting. Agence France-Presse reported that at least 30,000 people from Myanmar, mostly the ethnically Chinese Kokang, had crossed the border into Yunnan.