The number of people uprooted within their own countries by war and conflict rose last year to a record 40.8 million, a report published on May 10 found.
"This is the highest figure ever recorded and twice the number of refugees worldwide," said Jan Egeland, head of the Norwegian Refugee Council, co-authors of the report with the Geneva-based Internal Displacement Monitoring Center.
Some 8.6 million newly displaced people were recorded in 2015, including 4.8 million in the Middle East and North Africa.
"Displacement...has snowballed since the Arab Spring uprising in 2010 and the rise of the Islamic State," said the report, with Yemen, Syria, and Iraq accounting for more than half of the total.
Outside the Middle East, the countries with the highest numbers of people fleeing were Afghanistan, Central African Republic, Colombia, Democratic Republic of Congo, Nigeria, South Sudan, and Ukraine.
The report also said 19.2 million people were internally displaced last year by disasters. India, China and Nepal accounted for the highest numbers with 3.7 million, 3.6 million, and 2.6 million, respectively.