In the largest single rescue, some 250 Eritrean migrants were rescued in the waters between Malta and the Italian island of Lampedusa, ANSA reported Tuesday.
That's the same area where more than 200 people are believed to have drowned when a migrant boat capsized Friday.
The Italian coast guard and navy rescued 80 people from another boat.
Passengers from both boats were taken to a holding center on Lampedusa.
Some 80 people were rescued from a large raft stalled in Libyan waters, rte.ie reported.
Italian port authorities said they ordered a merchant ship in the area to pick up the migrants and take them to Pozzallo, a town on the southern tip of Sicily.
Six Tunisians were rescued by Italian police 35 miles southwest of the Sicilian city of Marsala.