The UN High Commissioner for Refugees is calling on countries to open their borders to migrants fleeing from the violence in Libya - sparking a clash with Italy, which has warned of a "disaster".

Refugees leaving Libya (R)

Libya is a transit point for many African and Middle Eastern migrants who are trying to reach Europe. There are an estimated 1.3million migrants living in Libya, including several thousand UN-registered refugees.

Colonol Gaddafi plays a vital role in controlling migration into Europe and last year signed an agreement with Italy, agreeing to stop migrants reaching the Italian coast.

This controversial 'push back' deal saw Italy hand over boat loads of migrants to the Libyan authorities, when they were found in Italian waters. In August last year Gaddafi gave a speech warning that Europe would 'turn black' if if wasn't tougher in turning back immigrants, and asked for millions of Euros in exchange for his cooperation.

On Sunday Gaddafi threatened to stop this cooperation if the EU encourages protests against him.

Laura Padoan - a spokeswoman for the UN High Commissioner for Refugees (UNHCR) - told Channel 4 News that this means refugees are even more vulnerable.

"What we are calling for is open borders to enable people who are in need of protection to get it." UNHCR spokeswoman Laura Padoan

"Before the unrest we had registered over 8,000 refugees in Libya, from African countries such as Somalia and Eritrea and also Iraq and Palestine," she said.

"These are people who have fled very insecure places, where they are threatened with violence. Migrants are seen with suspicion, they are already an incredibly vulnerable group of people. They feel trapped, they can't leave and are hiding. If some have no food at all they are still not leaving home. Some Eritrean men have been attacked in the night and they have no safe place to go."

She said the UNHCR want Italy to stop sending migrants back to Libya: " Either Libyans fleeing in fear of persecution or other African migrants could start to arrive in Italy so what we are calling for is open borders to enable people who are in need of protection to get it."

Italian plea

But Italian interior minister Roberto Maroni has called for help from the international community, saying: "This is not just a problem for Italy, it's a problem for Europe and the world. This is a catastrophic humanitarian situation."

He estimated that a million refugees could flee from north Africa to Europe because of the current unrest. The Italian Government has formally requested £84million to deal with extra arrivals.

Florent Geel, head of the Africa bureau at the International Federation for Human Rights, told Channel 4 News that his organisation is very concerned about the fate of migrants still living in Tripoli.

He said: "There are mercenaries in Libya and large numbers are from Nigeria, Chad and Mali. So they are black and African which means that all black people are seen as militias. This is very concerning for us.

"We have heard that some militias are forcibly recruiting Africans, although most are still being paid."

But even for migrants who are in Libya legally there are huge problems. An estimated 50,000 Bangladeshis are in the country, mainly low paid construction workers. The Bangladesh Government is trying to get help from the Red Cross and the International Organisation on Migration.

The Daily Star newspaper in Dhaka is reporting that a group of about 70 Bangladeshi workers are trapped in a warehouse near Tripoli airport, unable to leave because of armed gangs.

'We are prepared for a large exodus'

In addition to fears over the protection of refugees within Libya, the UN says it is preparing for a mass movement of people across the Tunisian border.

Laura Padoan said: "We have seen a large flow of people at the Tunisian-Libyan border, mostly Tunisian nationals who have been working in Libya. But there have also been Turks, Moroccans, West Africans as well as Libyans. We are looking at locations to build a camp near the border and are flying relief materials to the border. We have assistance items for around 10,000 people. We are prepared for a large exodus."

But despite pleas from the UN European Governments remain nervous about the prospect of mass migration from north Africa. The Italian foreign minister Franco Frattini told journalists: "We are very concerned about the migratory flows impact that would be one of the consequences of the turbulences. "

According to the International Organisation of Migration, 30,000 people have already left Libya, mainly Tunisians and Egyptians. Most have crossed into their own countries. Last week several thousand Tunisians arrived on the Italian island of Lampedusa and the European Parliament held an emergency debate on what could be done to help stop the movement of people.