Chinese state media say China and Kazakhstan are holding an anti-terrorism drill on their border, with armed helicopters and anti-riot vehicles.
The Xinhua news agency says 700 border police are carrying out the drill in Yining in China's northwest region of Xinjiang.
Special forces and law enforcement agents are to simulate a battle in which they force the enemy into a narrow valley, using traditional and modern methods of combat.
The three-day drill began Thursday in Kazakhstan's Almaty region.
The joint exercise is the first of its kind between China and Kazakhstan under the framework of the Shanghai Cooperation Organization, a regional security alliance that also includes Russia, Kyrgyzstan, Tajikistan and Uzbekistan.
China and Kazakhstan have also cooperated on an oil pipeline, which will deliver about 15 percent of China's petroleum imports in the future.