GENEVA (AFP) - The United Nations' top official in charge of migration said Tuesday that the crisis rocking Europe needs a "global response", insisting that countries worldwide must be asked to do their share.

"We should have a European response as part of a global response," UN Special Representative for Migration and Development Peter Sutherland told reporters in Geneva, hinting at the need for an international conference "where every country is held up to the spotlight and asked what they are doing."

Europe is dealing with hundreds of thousands of migrants -- many of them refugees fleeing violence in places like Syria -- pouring across the Mediterranean and taking a land route up through the continent.

Syria's neighbours are meanwhile struggling to host more than four million refugees from the war-ravaged country.

Sutherland insisted geographical proximity to a crisis should not determine who takes in refugees, pointing out that during the Vietnam War, refugees were welcomed into countries around the globe.

The same, he said, was true following the Hungarian revolution in 1956, when an international conference was held to help distribute the some 200,000 people who fled the Soviet crackdown.

"I believe that we, in the United Nations have to drive... a much more proactive response by the international community," he said.

"We have to find a method, perhaps as we did in 1956 in the conference that took place then, to get specific commitments from every state in regard to taking refugees and financially contributing to dealing with the crisis which we now face," he added.

He also insisted that there needs to be a system to evaluate who constitutes a refugee that is consistent across all nations, noting that currently different countries are using different criteria.  

In the current crisis, the assessment of a person's right to refugee status should be made before they cross the Mediterranean to Europe, he suggested.

Sutherland also stressed that sending aid money to help Syrians at home or in the region should not be seen as a substitute to taking in a fair share of refugees.

"Buying your way out of this is not satisfactory," he said, pointing out that a number of the wealthy Gulf states had been very generous in their contributions, but had taken in very few refugees.

The same, he said, is true of the United States and Britain.

Sutherland called for a much fairer distribution of the refugee burden within Europe, pointing out that only five European countries have taken 72 percent of all refugees, while others take "virtually none".

"History will judge this as a defining moment for Europe, a Europe that proclaimed itself to be created on the principle of values," he said.