Up to 500 people are still missing from a migrant boat that sank off Greece, the UN human rights office says.
Large numbers of women and children were among those missing in the “horrific tragedy” that left 78 people dead, said spokesman Jeremy Laurence.
The appalling loss of life underscored the need to bring people smugglers to justice, he added.
But it also made clear that search and rescue at sea was a “legal and humanitarian imperative”.
In a joint statement with the International Organization for Migration, the refugee agency said any search and rescue action had to be conducted to prevent loss of life.
Since the fishing boat carrying up to 750 people went down 50 nautical miles of Pylos in southern Greece, the role of the coastguard has come under increasing scrutiny.