Syrian refugee children play around a tent, at a tented settlement in Akkar, northern Lebanon ahead of a powerful winter storm sweeping Lebanon January 6, 2015. [Photo/Agencies]

The Middle East and North Africa has become the main region of origin of refugees, overtaking the Asia and Pacific region that held the top spot for more than a decade.

Afghan refugees, the biggest group for three decades, have fallen to second place, with 2.6 million hosted by Pakistan and Iran at mid-year, it said. Somalis ranked as the third largest refugee group at 1.1 million.

Syria's neighbors - Lebanon, Iraq, Jordan and Turkey - continue to bear the brunt of the crisis.

"With 257 refugees per 1,000 inhabitants, Lebanon remains the country with the highest refugee density at mid-2014," UNHCR said, noting that Jordan ranked second.

Sweden, with 12 refugees per 1,000 inhabitants, is the only industrialised country among major hosts, ranking 10th, it said.