Europe's top official for migration is deploring the plight of thousands of refugees and other migrants in camps on Greece's eastern Aegean island of Lesbos who face harsh winter conditions.

Dimitris Avramopoulos, the European Union's commissioner for migration, says solutions must be found immediately.

Avramopoulos was visiting Lesbos Wednesday, accompanied by Greece's migration minister.

More than 5,000 people live in overcrowded camps on Lesbos, and hundreds had to be evacuated from tents that had been covered by snow during a cold spell this month.

More than 62,000 refugees and other migrants have been stuck in Greece since a series of Balkan border closures and an EU-Turkey deal on stemming migration last March.

Avramopoulos also promised action to reduce congestion in island camps.