Dozens of refugees are feared dead after two boat tragedies left rescuers scouring the seas for those who had set out on risky crossings after fleeing war and poverty in their homelands.

Austria said 71 refugees including a baby girl were found dead in an abandoned freezer truck, while Libya recovered the bodies of 82 migrants washed ashore after their overcrowded boat sank on its way to Europe and scores more were feared dead.