tripoli least 31 migrants die boat sink libya western coast saturday 200 others pick coastguard bring back port tripoli officials say migrants two boat coast near garabulli east tripoli one already sink coastguard arrive scene say abu ajala amer abdelbari coast guard commander boat sink spread sea try swim towards coast say 60 people able save cling remain boat another 140 migrants pick second boat say dead include number children bring back tripoli naval base unload white plastic body bag libya main departure point mostly african migrants try cross europe smugglers usually pack flimsy inflatable boat often break sink migrants pick international vessels take italy 115,000 land far year although increase number intercept libya european-backed coastguard return north african country since july sharp drop cross though week see renew surge departures nearly 3,000 migrants know die miss try cross europe sea year majority libya italy international organization migration say friday since 2000 mediterranean far world deadly border migrants thirty-one body recover migrant boat sink libya