At least 21 people died and 213 illegal immigrants are still missing after three boats sank in a storm off Libya, the International Organisation for Migration said on Tuesday. "A boat with 257 migrants on board sank on Sunday off the coast of Libya. Twenty-three people were saved and 21 bodies were retrieved", said Laurence Hart, the IOM chief of mission in Tripoli. An earlier IOM toll out of its Geneva headquarters put the number of missing at 300.