In this photo taken on Wednesday, February 17, 2016, a volunteer fighter with the Syrian Government forces sits atop a tank in the province of Raqqa, Syria. In recent weeks, Syrian government forces captured dozens of villages and towns across the country. (Photo by Alexander Kots/Komsomolskaya Pravda via AP Photo)

Riot police scuffle with pro-democracy students after hundreds of protesters stormed into a restricted area at the government headquarters, after a rally ahead of the October 1 “Occupy Central” civil disobedience movement in Hong Kong September 27, 2014. Hong Kong riot police used pepper spray on Saturday to disperse dozens of students who had stormed government headquarters, but an equal number held their ground in protests against Beijing's tightening grip on the city. (Photo by Tyrone Siu/Reuters)

A cat wears a “Tsunagaru Col” gadget next to a smart phone displaying the connected app, at the Anicall Corp booth during the Wearable Device Technology Expo in Tokyo January 14, 2015. The gadget (“Tsunagaru” means connection) for animals tracks information about pets, such as the location and other animals the pet might be interacting with, with the purpose of providing “social networking” for animals. The expo runs until January 16 as a part of Japan's largest electronic exhibition expected to attract around 77,000 visitors, according to organisers. (Photo by Yuya Shino/Reuters)

A street vendor warms his foot around a fire during cold weather in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria, January 4, 2016. (Photo by Khalil Ashawi/Reuters)

Muhannad al-Kadiri (R),18, and Ibrahim Eid, 16, demonstrate their Parkour skills over a military vehicle in the rebel-held city of Inkhil, west of Deraa, Syria, February 4, 2017. (Photo by Alaa Al-Faqir/Reuters)

A female member of the Ahbab Al-Mustafa Battalion holds a gun as she undergoes military training in Aleppo's Salaheddine district, June 24, 2013. (Photo by Muzaffar Salman/Reuters)

A painting of Chinese President Xi Jinping holding an umbrella is seen on the toilet wall in a guesthouse in Hong Kong December 30, 2014. Set up in a small apartment in the Causeway Bay shopping district, the guesthouse that gives what it calls “Umbrella Revolution Occupation Experience” charges guest HK$100 (US$13) a night to stay in a tent surrounded by pro-democracy banners, a cardboard cutout of President Xi Jinping holding a yellow umbrella, and serve toilet paper printed with the face of embattled leader of Hong Kong chief executive Leung Chun-ying. (Photo by Tyrone Siu/Reuters)

Syrians try to rescue a dead body under the debris of a collapsed building after Syrian and Russian army carried out an airstrike on opposition controlled residential area at Merce neighborhood of Aleppo, Syria on September 23, 2016. (Photo by Jawad al Rifai/Anadolu Agency/Getty Images)