By Ahmed Elumami TRIPOLI (Reuters) - A boat packed with mainly African migrants bound for Italy sank off the Libyan coast on Thursday and officials said up to 200 might have died. A security official in the western town of Zuwara, from where the overcrowded boat had set off, said there had been around 400 people on board. By late in the evening, the Libyan coast guard rescued around 201, of which 147 were brought to a detention facility for illegal migrants in Sabratha, west of Tripoli, the official said, asking not to be named.