A Type 89 infantry fighting vehicle of Japan's Ground Self-Defence Force is seen during an exercise with the 1st Airborne Brigade at Narashino training ground in Funabashi, Chiba prefecture on January 13, 2019. (KAZUHIRO NOGI/AFP/Getty Images)
An image taken from a video obtained by AFPTV shows the moment a drone exploded above Yemen's al-Anad airbase in in the government-held southern province of Lahj on January 10, 2019. - Six soldiers were killed in a rebel drone attack on Yemen's largest airbase, hospital sources told AFP. Another 12 people were wounded in the attack on the airbase, medics said. (NABIL HASAN/AFP/Getty Images)
An image taken from a video obtained by AFPTV shows a wounded Yemeni soldier being carried by comrades after a drone exploded above Yemen's al-Anad airbase in the government-held southern province of Lahj on January 10, 2019. - Six soldiers were killed in a rebel drone attack on Yemen's largest airbase, hospital sources told AFP. Another 12 people were wounded in the attack on the airbase, medics said. (NABIL HASAN/AFP/Getty Images)
Syrian soldiers sit atop a tank being transported near the northern town of Manbij, on January 12, 2019. (Photo by George OURFALIAN / AFP)
CH-47JA helicopters from Japan's Ground Self-Defence Force take part in an airborne exercise with the 1st Airborne Brigade at Narashino training ground in Funabashi, Chiba prefecture on January 13, 2019. (KAZUHIRO NOGI/AFP/Getty Images)
Dassault Aviation's Rafale fighter jets sit on an assembly line in Merignac, southwestern France, on January 14, 2019. - French Defence Minister, Florence Parly, launched on January 14, 2019 a 1,9-billion-euro-program for the new F4 standard of the Dassault Rafale combat aircraft. (MEHDI FEDOUACH/AFP/Getty Images)
Dassault Aviation employees work on an assembly line for the Rafale fighter jets in Merignac, southwestern France, on January 14, 2019. - French Defence Minister, Florence Parly, launched on January 14, 2019 a 1,9-billion-euro-programme for the new F4 standard of the Dassault Rafale combat aircraft. (MEHDI FEDOUACH/AFP/Getty Images)
A military helicopter monitors the situation at the Austrian-German border at Kufstein after heavy snowfall in Austria on January 10, 2019. (JOE KLAMAR/AFP/Getty Images)
Paratroopers of Japan's Ground Self-Defence Force 1st Airborne Brigade jump from a Kawasaki C-2 heavy transport aircraft during an airborne exercise at Narashino training ground in Funabashi, Chiba prefecture on January 13, 2019. (KAZUHIRO NOGI/AFP/Getty Images)
A track vehicle of the German armed forces Bundeswehr drives through the snow to supply the cut off Buchenhoehe settlement area in Berchtesgaden, southern Germany, on January 10, 2019. (BERND MARZ/AFP/Getty Images)
Border security force (BSF) camel mounted soldiers during a rehearsal for the forthcoming Republic Day parade near India Gate in New Delhi on January 10, 2019. - India will celebrate its 70th Republic Day on January 26. (DOMINIQUE FAGET/AFP/Getty Images)