Photo taken on Sept. 7, 2018 shows an armed vehicle displayed at the 26th International Defense Industry Exhibition in Kielce, Poland. The 26th edition of the International Defense Industry Exhibition concluded here on Friday. (Xinhua/Chen Xu)

Photo taken on Sept. 7, 2018 shows bullets displayed at the 26th International Defense Industry Exhibition in Kielce, Poland. The 26th edition of the International Defense Industry Exhibition concluded here on Friday. (Xinhua/Chen Xu)

Photo taken on Sept. 7, 2018 shows exhibits displayed at the 26th International Defense Industry Exhibition in Kielce, Poland. The 26th edition of the International Defense Industry Exhibition concluded here on Friday. (Xinhua/Chen Xu)

Different kinds of rifles are displayed at the 26th International Defense Industry Exhibition in Kielce, Poland, on Sept. 7, 2018. The 26th edition of the International Defense Industry Exhibition concluded here on Friday. (Xinhua/Chen Xu)

An armed helicopter is displayed at the 26th International Defense Industry Exhibition in Kielce, Poland, on Sept. 7, 2018. The 26th edition of the International Defense Industry Exhibition concluded here on Friday. (Xinhua/Chen Xu)

An armed helicopter is displayed at the 26th International Defense Industry Exhibition in Kielce, Poland, on Sept. 7, 2018. The 26th edition of the International Defense Industry Exhibition concluded here on Friday. (Xinhua/Chen Xu)