The rescues, from 13 boats and nine motorized rubber dinghies, took place Friday. The coast guard said Saturday that 17 migrants were found dead aboard one of the vessels. In all, 4,243 rescued migrants were being brought to Italian harbors.

Smugglers are reaping millions by overcrowding unseaworthy boats with migrants on Libya’s Mediterranean coast to set out for Italian shores. The migrants are fleeing war, persecution or poverty in Africa, the Mideast and elsewhere.

Cargo ships and Irish and German navy vessels helped Italian military craft in Friday’s rescues. Italy has demanded its European partners help more with migrants, who have been coming in huge numbers this year.