Italy’s coastguard says a major operation is under way to rescue up to 3,000 migrants off the coast of Libya.

The coastguard received SOS calls from 18 vessels – four boats and 14 rubber dinghies, Italian news agency Ansa said.

At least 1,200 people have already been rescued from five of the boats, in one of the largest such operations to date.

The route from Libya to Italy is one of the busiest for migrants trying to enter Europe.

Of the 264,500 migrants the United Nations says have crossed the Mediterranean so far this year, close to 104,000 have landed in Italy. Another 160,000 arrived in Greece.