GENEVA -- A record 33.3 million people worldwide were displaced by conflict and violence inside their own nations in 2013, UN and Norwegian officials said Wednesday.

The increase of 4.5 million above the 2012 total was driven largely by Syria's civil war, now in its fourth year, which activists estimate has killed 150,000 people.

The heads of the UN refugee agency and Norwegian Refugee Council reported that 8.2 million fled their homes in the last year, including about 3.5 million in Syria alone. The other two-thirds of the 33.3 million displaced by war worldwide had fled in previous years.

Every 60 seconds another family within Syria flees the civil war, according to the figures.

"Syria is the epicenter of violent, forced displacement," Jan Egeland, secretary general of the Norwegian agency, told reporters in Geneva.

He said the figures are the worst since the genocides in Rwanda and Bosnia in the 1990s, when the figures spiked at 28 million, but that many of the displaced people are struggling to survive crises that are decades old but still in need of "durable solutions."

The figures compiled by Geneva-based Internal Displacement Monitoring Centre, part of the Norwegian agency, only cover 58 countries. But they show that 63 per cent of those internally displaced worldwide are struggling to live in five countries: Syria, 6.5 million; Colombia, 5.7 million; Nigeria, 3.3 million; Democratic Republic of the Congo, 2.9 million, and Sudan, 2.4 million

"These are people in absolute crisis," said Egeland, who was the UN's top humanitarian official from 2003 to 2006. "They are the most vulnerable of humankind."

UN High Commissioner for Refugees Antonio Guterres said the disturbing upward trend in the figures shows that "what we are witnessing in today's world is a multiplication of conflicts, and at the same time it looks like old conflicts never die."