Members of Emirates forces demonstrate their skills during a military show at the opening ceremony of the International Defence Exhibition and Conference (IDEX) in Abu Dhabi, United Arab Emirates February 19, 2017. REUTERS/Stringer - RTSZCB7

Abu Dhabi Crown Prince Sheikh Mohammed bin Zayed al-Nahayan (2nd L), Prime Minister and Vice-President of the United Arab Emirates and ruler of Dubai Sheikh Mohammed bin Rashid al-Maktoum (2nd R), and Sudan's President Omar al-Bashir (R) attend the opening ceremony of the International Defence Exhibition and Conference (IDEX) in Abu Dhabi, United Arab Emirates February 19, 2017. REUTERS/Stringer - RTSZCD3

A visitor looks at munitions on display during the International Defence Exhibition and Conference (IDEX) in Abu Dhabi, United Arab Emirates February 19, 2017. REUTERS/Stringer - RTSZCPE

Members of the Emirates forces demonstrate their skills during a military show at the opening ceremony of the International Defence Exhibition and Conference (IDEX) in Abu Dhabi, United Arab Emirates February 19, 2017. REUTERS/Stringer - RTSZCBM

Flames and smoke are seen during a military show at the opening ceremony of the International Defence Exhibition and Conference (IDEX) in Abu Dhabi, United Arab Emirates February 19, 2017. REUTERS/Stringer TPX IMAGES OF THE DAY - RTSZC8V

Aircrafts perform during a military show at the opening ceremony of the International Defence Exhibition and Conference (IDEX) in Abu Dhabi, United Arab Emirates February 19, 2017. REUTERS/Stringer TPX IMAGES OF THE DAY - RTSZC9J

Visitors attend the opening ceremony of the International Defence Exhibition and Conference (IDEX) in Abu Dhabi, United Arab Emirates February 19, 2017. REUTERS/Stringer - RTSZCCA

Aircrafts perform as members of the Emirates forces demonstrate their skills during a military show at the opening ceremony of the International Defence Exhibition and Conference (IDEX) in Abu Dhabi, United Arab Emirates February 19, 2017. REUTERS/Stringer - RTSZCE5

Members of the Emirates forces demonstrate their skills during a military show at the opening ceremony of the International Defence Exhibition and Conference (IDEX) in Abu Dhabi, United Arab Emirates February 19, 2017. REUTERS/Stringer - RTSZCE8

Visitors look at vehicles on display during the International Defence Exhibition and Conference (IDEX) in Abu Dhabi, United Arab Emirates February 19, 2017. Image used for illustrative purpose.

Members of the Emirates forces demonstrate their skills during a military show at the opening ceremony of the International Defence Exhibition and Conference (IDEX) in Abu Dhabi, United Arab Emirates February 19, 2017. REUTERS/Stringer - RTSZCBL

Aircrafts perform during a military show at the opening ceremony of the International Defence Exhibition and Conference (IDEX) in Abu Dhabi, United Arab Emirates February 19, 2017. REUTERS/Stringer - RTSZC9E

Participants take part in a military show at the opening ceremony of the International Defence Exhibition and Conference (IDEX) in Abu Dhabi, United Arab Emirates February 19, 2017. REUTERS/Stringer - RTSZCEM

Members of the Emirates forces demonstrate their skills during a military show at the opening ceremony of the International Defence Exhibition and Conference (IDEX) in Abu Dhabi, United Arab Emirates February 19, 2017. REUTERS/Stringer - RTSZCBB

Flames and smoke are seen during a military show at the opening ceremony of the International Defence Exhibition and Conference (IDEX) in Abu Dhabi, United Arab Emirates February 19, 2017. REUTERS/Stringer - RTSZCBC

Sudan's President Omar al-Bashir (2nd L) arrives at the opening ceremony of the International Defence Exhibition and Conference (IDEX) in Abu Dhabi, United Arab Emirates February 19, 2017.

Members of the Emirates forces demonstrate their skills during a military show at the opening ceremony of the International Defence Exhibition and Conference (IDEX) in Abu Dhabi, United Arab Emirates February 19, 2017. REUTERS/Stringer - RTSZCE4

A man sits in a vehicle on display during the International Defence Exhibition and Conference (IDEX) in Abu Dhabi, United Arab Emirates February 19, 2017.