Italy has seen a rise in so-called “phantom” boat arrivals as traffickers ferry migrants across the Mediterranean from Tunisia rather than Libya without being spotted, a prosecutor warned Saturday. The closing window of opportunity to reach Europe before the onset of winter has also seen a spike in the numbers of crossings, just ahead of a meeting of interior ministers on the hot-button topic of migration on Monday in Malta. Of the more than 6,620 people to have arrived in Italy since the start of 2019, some 5,500 have done so autonomously, managing to approach the coast or land without...