A Wiesel combat vehicle of the German Bundeswehr armed forces takes part in a demonstration for visitors prior to military exercises on September 28, 2011 near Munster, Germany. The Bundeswehr has instituted far-reaching changes in recent years, including an end to compulsory military service. (Photo by Sean Gallup/Getty Images)

Soldiers from Japan's Ground Self Defense Force come ashore in amphibious assault vehicle as they train alongside U.S. Marines during the bilateral annual Iron Fist military training exercise in Camp Pendleton, California February 26, 2016. (Photo by Mike Blake/Reuters)

A woman covers her face as a fire burns in the middle of town during an anti-G20 protest on July 7, 2017 in Hamburg, Germany. Authorities are braced for large-scale and disruptive protests as Leaders of the G20 group of nations arrive in Hamburg for the July 7-8 G20 summit. (Photo by Leon Neal/Getty Images)

U.S. soldiers from 145th Field Artillery Battalion deployed from the United States fire Paladin self propelled gun during the Foal Eagle training exercise at firing point 180 at the Rodriguez Live Fire Range on March 15, 2012 in Pocheon, South Korea. (Photo by Chung Sung-Jun/Getty Images)

Martin Weitzendoerfer, diver of Frankfurt's firefighter rescue brigade, leaves a frozen lake during a rescue exercise in Frankfurt, Germany, January 24, 2017. (Photo by Kai Pfaffenbach/Reuters)

A Japanese Ground Self-Defense Force Type 92 Mine sweeping vehicle fires a rocket behind a Type 74 armoured tank during an annual training session, which is based on a scenario to defend or retake islands in Japanese territory, near Mount Fuji at Higashifuji training field in Gotemba, west of Tokyo, August 18, 2015. (Photo by Yuya Shino/Reuters)

Demonstrators protest during a rally against Venezuelan President Nicolas Maduro, in Caracas on April 19, 2017. Venezuela braced for rival demonstrations Wednesday for and against President Nicolas Maduro, whose push to tighten his grip on power has triggered waves of deadly unrest that have escalated the country' s political and economic crisis. (Photo by Juan Barreto/AFP Photo)

A Polish Army tank takes part in the NATO Noble Jump exercise on a training range near Swietoszow Zagan, Poland, Thursday, June 18, 2015. (AP Photo/Alik Keplicz)