The UN refugee agency is putting pressure on Europe to help Italy defuse the "unfolding tragedy" of tens of thousands of migrants and refugees flooding its shores.

The move comes as interior ministers of France, Germany and Italy prepare to meet in Paris on Sunday to discuss a "coordinated approach" to help Rome.

Italy needs more international support to cope with a growing number of people who have braved a perilous Mediterranean crossing to reach Europe this year, Filippo Grandi, the UN high commissioner for refugees, said on Saturday in a statement.

"What is happening in front of our eyes in Italy is an unfolding tragedy.

"In the course of last weekend, 12,600 migrants and refugees arrived on its shores, and an estimated 2,030 have lost their lives in the Mediterranean since the beginning of the year."

Italy, he said, was "playing its part" in taking in those rescued and offering protection to those in need.

"These efforts must be continued and strengthened. But this cannot be an Italian problem alone."

Last week, Italy threatened to close its doors to people arriving on boats that were not flying Italian flags.

Europe has to get fully involved through an "urgent distribution system" of migrants and refugees and should widen legal channels so that migrants can be admitted, Grandi said.

He also called for greater international efforts to tackle the causes of migration, to protect people and to fight trafficking.

READ MORE: Greeks protest government crackdown on refugee squats

Since the beginning of the year, 83,650 people have reached Italy by sea, an increase of nearly 20 percent compared with the same period last year, UN figures show.

Nearly all of Italy's 200,000 places for accommodating migrants have been filled.

Many of the people arriving need healthcare and support. A large percentage of them are non-accompanied children and victims of sexual violence, says the UN.

The number of migrant children arriving on their own rose twofold between 2015 and 2016, reaching 25,846 at the end of last year.

Worst migration crisis

Europe has been grappling with the worst migration crisis since the end of World War II with an influx of people fleeing the wars in Syria and Iraq while others from Africa are seeking an escape from poverty or political persecution.

And there continue to be flare-ups of violence prompted by the tensions among the migrants and refugees gathered in western Europe.

In the northern French port city of Calais, riot police stepped in over the past two days to break up fighting among African asylum seekers armed with sticks and rocks.

Fighting between Eritreans and Ethiopians on Saturday left 16 people injured, with police making 10 arrests.

That followed brawls on Friday night when security forces used tear gas to disperse the feuding sides, Calais Mayor Philippe Mignonet said.

"In the past 12 hours, in terms of violence, there's been an escalation," he told AFP.

Calais has for years been a magnet for migrants and refugees hoping to cross the Channel to Britain.

Last October, France broke up the notorious tent camp known as "the Jungle" transferring thousands of migrants to centres around the country.

But hundreds remain near the port, mostly Africans and Afghans, who clash sporadically with police as they make nightly attempts to stow away onto trucks heading across the Channel to Britain.

Last month, a Polish driver was killed when his truck burst into flames after hitting a roadblock set up by migrants hoping to slow the traffic to make it easier to jump onto vehicles.

French President Emmanuel Macron's new government has ruled out building a reception centre for asylum seekers in Calais, saying it would only encourage more people to come, and has promised to reinforce security.