A fighter belonging to Jaish al-Islam (Islam Army) runs to take cover near the frontline on March 14, 2016 in the neighbourhood of Jobar, on the eastern outskirts of the capital Damascus. (Photo by Amer Almohibany/AFP Photo)

Participants play with water guns during the Sinchon Water Gun Festival in Seoul, South Korea, July 9, 2016. (Photo by Kim Hong-Ji/Reuters)

A large variety of weapons were for sale at the Washington County Fairgrounds Gun Show that drew thousands of people over the weekend, on March 22, 2013. (Photo by Gary Porter)

Mikhail Kalashnikov, the father of the world's most popular assault rifle, is handed an AK-74 November 23, 2002 in Izhevsk,1000 East km. from Moscow. November 23 marked the 55th anniversary of the release of the first Kalashnikov gun. According to the Moscow-based Center for Analysis of Strategic and Technologies some 70 million to 100 million Kalashnikovs have been built worldwide since 1947, compared about 7 million to Kalashnikov's Western rival the M-16 assault rifles. (Photo by Oleg Nikishin/Getty Images)

A Syrian boy receives treatment at a hospital in the regime-held part of Aleppo on October 13, 2016. Syrian state television said four children were killed by rebel rocket fire on a school in a western regime-held neighbourhood. (Photo by George Ourfalian/AFP Photo)

Men pull as a boy stands on a soap cutter in a soap factory in Idlib province, Syria January 30, 2016. (Photo by Ammar Abdullah/Reuters)

A young man with an amputated leg poses for a photograph standing by his broken artificial limb in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria March 20, 2016. Two university students forced to interrupt their studies have learnt to make and fit hundreds of new limbs in the past four years in opposition-held areas of Syria. A mobile clinic operating from a truck has gone some way to improve access to treatment. While most patients are between 15 and 45, the clinic also helps children and the elderly with replacement limbs. (Photo by Khalil Ashawi/Reuters)

A little girl holding her newborn sister waits for their turn in a queue during a vaccination campaign under the supervision of the Syrian Arab Red Crescent (SARC) humanitarian nonprofit organization, in the besieged Syrian town of Douma, Syria, 23 May 2017. According to a statement from SARC, in the city of Douma some 12,809 children under the age of five were immunized in a vaccination campaign to prevent measles and poliomyelitis. The campaign was the first of its kind with the participation of 100 volunteers. SARC has been delivering vaccines to 17 health centers approved for vaccination campaigns in towns and villages in the Eastern Ghouta area. (Photo by Mohammed Badra/EPA)