BRUSSELS (AP) — The Latest on immigration into Europe (all times local):

11:25 a.m.

A top European Union legal adviser says the Czech Republic, Hungary and Poland have been breaking EU law by refusing to comply with the bloc's migrant quota scheme.

In a legal opinion Thursday, Advocate General Eleanor Sharpston said the EU's highest court should rule that the three countries "have failed to fulfill their obligations under EU law."

EU nations agreed in 2015 to relocate 160,000 refugees from Italy and Greece as the countries buckled under the arrival of hundreds of thousands of migrants.

But the Czech Republic, Hungary and Poland took in almost none over the two years the scheme was in operation. The EU's executive Commission sought an explanation but they gave no satisfactory answers.

Sharpston's opinion is not legally binding, but such recommendations are usually followed by the European Court of Justice.

11: a.m.

A European top official says the situation in Greece's migrant camps is "explosive" and is urging the country's authorities to "urgently" transfer asylum-seekers from islands to the mainland as soon as possible.

Speaking at the end of a five-day visit in Greece, the Council of Europe's Commissioner for Human Rights Dunja Mijatovic said Thursday that "the situation of migrants, including asylum-seekers, in the Greek Aegean islands has dramatically worsened over the past 12 months."

She says there is "a desperate lack of medical care and sanitation in the vastly overcrowded camps I have visited. People queue for hours to get food and to go to bathrooms, when these are available."

Greek authorities are struggling to cope with a sharp rise in the number of arrivals over the summer months on Lesbos and other islands in the eastern Aegean Sea where European Union-funded camps are suffering severe overcrowding and outbreaks of violence.