Half a million Cambodians work abroad; many end up as slaves.
Rights groups question better grades for countries with which the U.S. seeks closer ties
Authorities don't know yet how many bodies are in each of the 139 grave sites.
Myanmar has up to now resisted calls for it to take part in meetings on the migrant crisis.
Madrid group praises Barcelona judge's decision to make employers cover prostitutes' social security.
Hundreds of migrants fleeing war zones in Africa and the Middle East have drowned in the "deadliest weekend ever in the Mediterranean", says UNHCR
In the worst incident, as many as 500 migrants are believed to have died after traffickers rammed their ship off Malta's coast last week