![A police dog acts in a drill in Harbin, northeast China\'s Heilongjiang Province, May 30, 2019. (Xinhua/Liu Song)](http://www.ecns.cn/hd/2019/05/31/626a775bde034ea98dfa106a655f93fa.jpg)
A police dog acts in a drill in Harbin, northeast China's Heilongjiang Province, May 30, 2019. (Xinhua/Liu Song)
![A police dog jumps in a drill in Harbin, northeast China\'s Heilongjiang Province, May 30, 2019. (Xinhua/Liu Song)](http://www.ecns.cn/hd/2019/05/31/5755757a3a654e47b58833047a254ec5.jpg)
A police dog jumps in a drill in Harbin, northeast China's Heilongjiang Province, May 30, 2019. (Xinhua/Liu Song)
![A police dog is trained in a drill in Harbin, northeast China\'s Heilongjiang Province, May 30, 2019. (Xinhua/Liu Song)](http://www.ecns.cn/hd/2019/05/31/46d87ab307f04111a0a841432011bece.jpg)
A police dog is trained in a drill in Harbin, northeast China's Heilongjiang Province, May 30, 2019. (Xinhua/Liu Song)
![A police dog sniffs in a drill in Harbin, northeast China\'s Heilongjiang Province, May 30, 2019. (Xinhua/Liu Song)](http://www.ecns.cn/hd/2019/05/31/a13235df214a4f429a21e2cc41cebf3e.jpg)
A police dog sniffs in a drill in Harbin, northeast China's Heilongjiang Province, May 30, 2019. (Xinhua/Liu Song)
![A police dog is trained in a drill in Harbin, northeast China\'s Heilongjiang Province, May 30, 2019. (Xinhua/Liu Song)](http://www.ecns.cn/hd/2019/05/31/5c6c40e1353247d6b22d0d29144ce567.jpg)
A police dog is trained in a drill in Harbin, northeast China's Heilongjiang Province, May 30, 2019. (Xinhua/Liu Song)
![A police dog is trained in a drill in Harbin, northeast China\'s Heilongjiang Province, May 30, 2019. (Xinhua/Liu Song)](http://www.ecns.cn/hd/2019/05/31/2056380402c8473a8681d9562c6f04a4.jpg)
A police dog is trained in a drill in Harbin, northeast China's Heilongjiang Province, May 30, 2019. (Xinhua/Liu Song)
![A police dog is trained in a drill in Harbin, northeast China\'s Heilongjiang Province, May 30, 2019. (Xinhua/Liu Song)](http://www.ecns.cn/hd/2019/05/31/a783723f742249cd9d52c9790c18a7f0.jpg)
A police dog is trained in a drill in Harbin, northeast China's Heilongjiang Province, May 30, 2019. (Xinhua/Liu Song)
![Police dogs and trainers are seen in a drill in Harbin, northeast China\'s Heilongjiang Province, May 30, 2019. (Xinhua/Liu Song)](http://www.ecns.cn/hd/2019/05/31/c07e033cbd85466ba990e42735de2aef.jpg)
Police dogs and trainers are seen in a drill in Harbin, northeast China's Heilongjiang Province, May 30, 2019. (Xinhua/Liu Song)
![A police dog is trained in a drill in Harbin, northeast China\'s Heilongjiang Province, May 30, 2019. (Xinhua/Liu Song)](http://www.ecns.cn/hd/2019/05/31/47622373ae7e4eaf9e492b5e9a89ee4e.jpg)
A police dog is trained in a drill in Harbin, northeast China's Heilongjiang Province, May 30, 2019. (Xinhua/Liu Song)