By Umberto Bacchi

LONDON (Thomson Reuters Foundation) - Italian police have broken up a criminal ring which smuggled at least 100 migrants from the northern city of Milan to other European countries in what authorities described as one of the biggest operations of its kind.

Italy has been on the frontline of Europe's immigration crisis. About 170,000 migrants reached Italy by sea in 2014 and 153,800 came in 2015. So far this year, more than 79,000 migrants have arrived, the vast majority of them Africans.

Police said they arrested and charged 10 people with smuggling offences, including the suspected ringleader, a 37-year-old Egyptian man. The arrests were made in raids across four northern provinces this week.

The suspects are accused of smuggling at least 100 people - mainly Syrians - out of Italy between September and October 2014.

A police official told the Thomson Reuters Foundation that after reaching Italy, the migrants would make their way to Milan where they would be met by smugglers offering to transport them to northern Europe for between 500 euros and 1,200 euros each.

The migrants would then be loaded into small vehicles and driven to their final destination in France, Germany, Denmark and the Netherlands, the official said.

During the investigation police seized a minivan carrying an entire family of seven, including four children.

"They were squeezed at the back in inhumane conditions," said the police official, who declined to be named.

The operation came as authorities stepped up their efforts against smuggling and trafficking gangs operating on both sides of the Mediterranean.

Almost 3,000 migrants more have died or gone missing in the Mediterranean this year, according to the International Organization for Migration.

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(Reporting by Umberto Bacchi @UmbertoBacchi, Editing by Katie Nguyen.; Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women's rights, trafficking, property rights and climate change. Visit http://news.trust.org)