Syria overtook Afghanistan to become the world's biggest source of refugees last year, while the number of people forced from their homes by conflicts worldwide rose to a record 59.5 million, the United Nations' refugee agency said Thursday.

Pointing to crises in Syria, Iraq, Yemen, Burundi and elsewhere, U.N. High Commissioner for Refugees Antonio Guterres said he doesn't expect any improvement in 2015.

"There is a multiplication of new crises," he said. "The Iraq-Syria crisis gained the dimension of a mega one ... and at the same time the old crises have no solutions."

The report comes at a time when Europe is grappling with how to deal with a flood of new migrants crossing the Mediterranean to escape the fighting in Syria, Libya and elsewhere.

UNHCR estimated that a total of 59.5 million people worldwide had been displaced by conflict by the end of last year — including 38.2 million displaced within their own countries. That was up from 51.2 million in 2013 — the previous highest since the U.N. began collecting numbers in the early 1950s. Syria alone accounted for 11.6 million of those people, the biggest single figure.

The agency counted nearly 3.9 million Syrian refugees in 107 countries last year, the fourth year of the country's civil war. That made it the leading source of refugees — pushing Afghanistan, which had held that status for more than 30 years, down to second place with 2.6 million refugees.

Syria's northern neighbor, Turkey, became the world's biggest refugee host with 1.59 million refugees. Pakistan, which had held that position for over a decade, was second with 1.51 million.

Over the course of last year, only 126,800 refugees returned to their home countries — the lowest number since 1983. The countries to which most people returned were Congo, Mali and Afghanistan.

Guterres said he was alarmed by "a staggering acceleration" in the number of people being forced from their homes over recent years.