ROME (Reuters) - Italian police said on Tuesday they had broken up a criminal network that smuggled mostly Syrian refugees across the Balkans to Western Europe.

International police forces arrested 21 people in Austria, Germany and Italy on suspicion of people smuggling, a police statement said. The arrests followed an investigation conducted by prosecutors in the northern Italian city of Como.

Most of those arrested were Syrian, while others were Algerian, Egyptian, Lebanese and Tunisian and were officially resident in the area around Como, Italy.

The criminal group organized transport for more than 200 migrants from 2014 to 2016, charging at least 500 euros ($560) each, according to prosecutors, who worked together with the EU's judicial cooperation unit, Eurojust.

The probe began in September last year after an Italian was arrested in Hungary "while driving in a vehicle with several illegal migrants", Eurojust said in a separate statement.

Italian police said the smuggling ring picked up migrants who had reached Hungary, and from there they were moved on toward Germany, Austria, and more rarely to France and Italy.

The so-called "Balkans route", used by hundreds of thousands of migrants last year, has been less popular since the European Union and Turkey agreed to stop boat crossings from Turkey to Greece earlier this year.

But boat crossings from Libya to Italy continue at about the same rate as before, with some 100,000 arrivals so far this year.

Migrants have flooded into Europe over the past three years from the Middle East, Africa and Asia, fleeing violence and poverty at home.

(Reporting by Steve Scherer and Gavin Jones; Editing by Alison Williams)