Milan , Italy ( CNN ) -- About 150 people were missing Wednesday after a boat capsized in the Mediterranean Sea , the Italian Coast Guard said . The boat was carrying about 200 passengers when it sank about 39 miles ( 62 kilometers ) west off the island of Lampedusa in Maltese waters , the Coast Guard said . Maltese authorities were heading the rescue operation with the Italian Coast Guard assisting . Darkness and poor weather hampered the search when the first rescue boats arrived early Wednesday morning , officials said . Since then , rescue vessels have rescued 48 people and were looking for the rest . The passengers are believed to be of Tunisian descent .
The boat was carrying 200 passengers , the Coast Guard says . 48 have been rescued . Poor weather hampers rescue efforts .