Kalei Ferrin,3, holds a sign up in support of gay rights during the San Diego gay pride parade July 16, 2011 in San Diego, California. About 200 active-duty troops and veterans from every branch of the military participated for the first time in the march as the ban on the government policy on homosexuals serving in armed forces, or “Don't ask Don't Tell”, remains in flux in the justice system. (Photo by Sandy Huffaker/Getty Images)

Militant Islamist fighters take part in a military parade along the streets of Syria's northern Raqqa province June 30, 2014. The fighters held the parade to celebrate their declaration of an Islamic “caliphate” after the group captured territory in neighbouring Iraq, a monitoring service said. The Islamic State, an al Qaeda offshoot previously known as Islamic State in Iraq and the Levant (ISIL), posted pictures online on Sunday of people waving black flags from cars and holding guns in the air, the SITE monitoring service said. (Photo by Reuters/Stringer)

A student attending a winter military camp reacts during a training session in Ansan, south of Seoul January 3, 2013. Hundreds of students between 11 and 17 years old attend winter boot camp training courses every year. The winter courses range from 4 to 14 days at the Blue Dragon Camp run by retired marines, which also offers summer boot camp for students. (Photo by Kim Hong-Ji/Reuters)

Ratko Mladic makes his first appearance at the International Criminal Tribunal on June 3, 2011 in The Hague, Netherlands. Ex-Bosnian Serb army leader Ratko Mladic will make his first appearance at The Hague war crimes tribunal after being declared fit to stand trial. Mladic was arrested a week ago after going into hiding for the past 16 years and is charged with atrocities committed during the Bosnian war. (Photo Serge Ligtenberg/Getty Images )

A woman aims a World War II machine gun at a military show during celebration of the Defenders of the Fatherland Day in St.Petersburg, Russia, Tuesday, February 23, 2016. The day, celebrated in Russia on February 23, honors the nation's military and is a nationwide holiday. (Photo by Dmitri Lovetsky/AP Photo)

A woman waits at a polio immunisation health centre, in Maiduguri, Borno State, Nigeria, August 29, 2016. Nigeria's military has liberated large swathes of land from Boko Haram but a ride with an army convoy, all guns firing for fear of ambush, shows how far the northeast is from normality after a brutal Islamist insurgency that has displaced millions. (Photo by Afolabi Sotunde/Reuters)

A Ukrainian serviceman fires a 2S7 Pion self-propelled gun during military exercises near the village of Divychky in Kiev region, Ukraine, October 21, 2016. (Photo by Valentyn Ogirenko/Reuters)

A boy holds a machine gun at a military hardware exhibition during a swear-in ceremony for new recruits of the Russian military-patriotic club “Yunarmia” (Young army) in the Black Sea port of Sevastopol, Crimea, October 27, 2018. (Photo by Pavel Rebrov/Reuters)