ROME (Reuters) - Italy is investigating whether Islamic State is involved in organizing the passage of tens of thousands of migrants across the Mediterranean, its justice minister said on Wednesday.

Refugees and migrants struggle to jump off an overcrowded dinghy on the Greek island of Lesbos, after crossing in rough seas from the Turkish coast, October 2, 2015. REUTERS/Dimitris Michalakis

The Turkey to Greece migration route has been largely shut down since a repatriation deal was struck between the European Union and Ankara in March, but hundreds of people are arriving in Italy every day, mostly from Libya.

Criminal gangs have taken advantage of chaos in Libya to charge mainly sub-Saharan Africans, looking for a better life in Europe, hundreds of dollars to make the voyage.

“From the information available, there is an investigation underway focused on whether representatives of ISIS (Islamic State) have crucial roles in controlling and managing migrant flows to Italy,” Justice Minister Andrea Orlando told a parliamentary committee.

He told the hearing on immigration, Europe’s border-free Schengen accord and the activity of European police agency Europol that details of the investigation were secret.

“The risks we have to take on are high,” he said, adding there was also a suspicion the militants were trying to influence where in Italy migrants were eventually placed.

The militant group has made money by selling oil from fields it seized in the Middle East and North Africa and from plundering weapons and ammunition.

Militant groups have smuggled members into Europe among the migrants, German Chancellor Angela Merkel has said.

The migrants are taking often unseaworthy boats from Libya to Italy. A total of 4,027 migrants or refugees have died worldwide so far this year, three-quarters of them in the Mediterranean, the International Organization for Migration (IOM) said on Tuesday, a 35 percent increase on the global toll during the first seven months of 2015.

More than 257,000 migrants and refugees have entered Europe by sea this year, it said.