Italian prosecutors are investigating alleged threats by migrants against a tugboat crew who rescued them in the sea off Libya.
An Italian coast guard vessel brought back 67 migrants Thursday night to Trapani, in western Sicily.
Interior Minister Matteo Salvini has said a Sudanese and a Ghanaian among the migrants allegedly tried to hijack the tug so it wouldn't return them to Libya, where migrants have been tortured in crowded detention centers.
Salvini had demanded the migrants not be allowed to disembark.
After President Sergio Mattarella expressed humanitarian concerns Thursday, authorities gave docking permission. Young children and women, including an injured woman, were among the migrants rescued on Sunday by the Italian tug.
The tug's captain, saying the migrants were rebelling, asked Italy's coast guard to take the migrants.