BRUSSELS (AP) — A European top official says the situation in Greece's migrant camps is "explosive" and is urging the country's authorities to transfer asylum-seekers from islands to the mainland.

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."

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.

Mijatovic, who visited camps in Lesbos, Samos and Corinth, added that Greece should implement urgent measures "to address the desperate conditions in which thousands of human beings are living."