UN secretary-general Ban Ki-moon has said he is "horrified and heartbroken" by the latest migrant deaths in Austria and at sea.

In a rare statement issued under his name and not a spokesman, he stressed that a "large majority" of people undertaking such dangerous journeys are refugees who have the right to protection and asylum.

He called on all governments to act with compassion and humanity.

Mr Ban also said the conflicts and repression that force people to flee must be resolved. "The Syrian war, for example, has just been manifested on a roadside in the heart of Europe," he said.

He plans a "special meeting devoted to these global concerns" on September 30, during the annual General Assembly of world leaders at UN headquarters.