A ship carrying up to 600 refugees sank off the Libyan coast shortly after leaving Tripoli, a United Nations refugee agency says. The agency is trying to confirm what happened, but the continuing war makes an official accounting unlikely. Witnesses say they saw the ship break apart and bodies floating in the sea. At least three other boats leaving Libya in late March have disappeared, with hundreds feared dead. Deaths and disappearances of refugees fleeing unrest and repression in Africa are on the rise, agency spokeswoman Laura Boldrini says, as smugglers begin to use larger boats that they cannot control.