A Russian Armata T-15 mechanized infantry combat vehicle is on display during the annual international military-technical forum "ARMY" at Patriot Expocentre in Moscow Region, Russia August 21, 2018. REUTERS/Maxim Shemetov 

A BWP-1s amphibious tracked infantry fighting vehicle of Poland's 1st Mechanized Battalion of the 7th Coastal Defence Brigade is driven in front of an Abrams tank of the U.S. 1st Brigade Combat Team, 1st Cavalry Division during a joint military exercise near Drawsko-Pomorskie November 13, 2014. REUTERS/Kacper Pempel (POLAND - Tags: MILITARY POLITICS) 

A member of the U.S. 1st Brigade Combat Team, 1st Cavalry Division walks in front of a BWP-1s amphibious tracked infantry fighting vehicle of Poland's 1st Mechanized Battalion of the 7th Coastal Defence Brigade during a joint military exercise near Drawsko-Pomorskie November 13, 2014. REUTERS/Kacper Pempel (POLAND - Tags: MILITARY POLITICS) 

Members of Poland's 1st Mechanized Battalion of the 7th Coastal Defence Brigade with BWP-1s amphibious tracked infantry fighting vehicles take part in a joint military exercise with the U.S. 1st Brigade Combat Team, 1st Cavalry Division near Drawsko-Pomorskie November 13, 2014. REUTERS/Kacper Pempel (POLAND - Tags: MILITARY POLITICS) 

Members of Poland's 1st Mechanized Battalion of the 7th Coastal Defence Brigade with BWP-1s amphibious tracked infantry fighting vehicles take part in a joint military exercise with the U.S. 1st Brigade Combat Team, 1st Cavalry Division near Drawsko-Pomorskie November 13, 2014. REUTERS/Kacper Pempel (POLAND - Tags: MILITARY POLITICS) 

Poland's 1st Mechanized Battalion of the 7th Coastal Defence Brigade with BWP-1s amphibious tracked infantry fighting vehicles and the U.S. 1st Brigade Combat Team, 1st Cavalry Division with Abrams and Bradley IFV tanks fire during a joint military exercise near Drawsko-Pomorskie November 13, 2014. REUTERS/Kacper Pempel (POLAND - Tags: MILITARY POLITICS) 

Poland's 1st Mechanized Battalion of the 7th Coastal Defence Brigade with BWP-1s amphibious tracked infantry fighting vehicles and the U.S. 1st Brigade Combat Team, 1st Cavalry Division with Abrams and Bradley IFV tanks fire during a joint military exercise near Drawsko-Pomorskie November 13, 2014. REUTERS/Kacper Pempel (POLAND - Tags: MILITARY POLITICS) 

Members of Japan's Self-Defence Forces' infantry unit take part in the military's review during the annual troop review ceremony at Asaka Base in Asaka, near Tokyo October 27, 2013. Japanese Prime Minister Shinzo Abe, in an interview published on Saturday, said Japan was ready to be more assertive towards China as Beijing threatened to strike back if provoked. REUTERS/Issei Kato (JAPAN - Tags: POLITICS MILITARY) 

French soldiers take part in a training with Ivorian troops in Toumodi, before Ivorian troops depart for Mali, April 6, 2013. REUTERS/Luc Gnago (IVORY COAST - Tags: POLITICS MILITARY) 

German Bundeswehr armed forces soldiers, dressed as "insurgents", take part in a drill with the 4th company of the mechanized infantry battalion 411 at a military training area GUEZ (Gefechtsuebungszentrum) in Colbitz November 11, 2011. The soldiers are preparing for their deployment to the northern Afghan city of Kunduz, where they will be deployed in January 2012 as the Second Task Force Kunduz of the International Security Assistance Force (ISAF). REUTERS/Fabrizio Bensch (GERMANY - Tags: MILITARY) 

Members of Yemen's U.S.-trained counter-terrorism force arrive on a technical vehicle to field training near Sanaa November 9, 2010. Yemen needs more help from its allies to combat al Qaeda, its foreign minister said on Monday, just two days after the militant group said it had been responsible for sending U.S.-bound parcel bombs on two aircraft. REUTERS/Khaled Abdullah (YEMEN - Tags: POLITICS CIVIL UNREST MILITARY TRANSPORT) 

Firefighters next to an armoured vehicle spray a burning barricade with water during an operation to evict anti-government "red shirt" protesters from their encampment in Bangkok May 19, 2010. Thai troops and armoured vehicles broke through barricades of tyres and staves on Wednesday in a fresh offensive to evict thousands of anti-government protesters from their fortified camp in central Bangkok, witnesses said. REUTERS/Damir Sagolj (THAILAND - Tags: POLITICS CIVIL UNREST) 

An armoured vehicle approaches a barricade during an operation to evict anti-government "red shirt" protesters from their encampment in Bangkok May 19, 2010. Thai troops and armoured vehicles broke through barricades of tyres and staves on Wednesday in a fresh offensive to evict thousands of anti-government protesters from their fortified camp in central Bangkok, witnesses said. REUTERS/Caren Firouz (THAILAND - Tags: POLITICS MILITARY CIVIL UNREST) 

An armoured vehicle is obscured by smoke from a burning barricade during an operation to evict anti-government "red shirt" protesters from their encampment in Bangkok May 19, 2010. Thai troops and armoured vehicles broke through barricades of tyres and staves on Wednesday in a fresh offensive to evict thousands of anti-government protesters from their fortified camp in central Bangkok, witnesses said. REUTERS/Caren Firouz (THAILAND - Tags: POLITICS MILITARY CIVIL UNREST IMAGES OF THE DAY) 

A woman (L) takes pictures of firefighters spraying a burning barricade with water during an operation to evict anti-government "red shirt" protesters from their encampment in Bangkok May 19, 2010. Thai troops and armoured vehicles broke through barricades of tyres and staves on Wednesday in a fresh offensive to evict thousands of anti-government protesters from their fortified camp in central Bangkok, witnesses said. REUTERS/Damir Sagolj (THAILAND - Tags: POLITICS MILITARY CIVIL UNREST) 

An armoured vehicle destroys a barricade during an operation to evict anti-government "red shirt" protesters from their encampment in Bangkok May 19, 2010. Thai troops and armoured vehicles broke through barricades of tyres and staves on Wednesday in a fresh offensive to evict thousands of anti-government protesters from their fortified camp in central Bangkok, witnesses said. REUTERS/Damir Sagolj (THAILAND - Tags: POLITICS MILITARY CIVIL UNREST IMAGES OF THE DAY) 

An armoured vehicle breaks through a barricade during an operation to evict anti-government "red shirt" protesters from their encampment in Bangkok May 19, 2010. Thai troops and armoured vehicles broke through barricades of tyres and staves on Wednesday in a fresh offensive to evict thousands of anti-government protesters from their fortified camp in central Bangkok, witnesses said. REUTERS/Fayaz Kabli (THAILAND - Tags: POLITICS MILITARY CIVIL UNREST IMAGES OF THE DAY) 

Military vehicles are driven towards the Red Square during a night training exercise for a military parade in central Moscow, April 29, 2010. Russia will mark the 65th anniversary of the victory over Nazi Germany in 1945 with a military parade in Moscow's Red Square on May 9. REUTERS/Denis Sinyakov (RUSSIA - Tags: MILITARY ANNIVERSARY SOCIETY POLITICS) 

A demonstrator hurls rocks at the Venezuelan National Guard at the border crossing between Colombia and Venezuela in Cucuta, October 22, 2009. They are protesting against the Venezuelan National Guard's operation to stop the smuggling of food and fuel across the border. REUTERS/Manuel Hernandez (COLOMBIA CONFLICT POLITICS IMAGES OF THE DAY)