Tens of thousands of lifejackets abandoned on the Greek island of Lesbos by migrants have been described as an "ecological timebomb".

Authorities on the island say they do not have the capacity to dispose of the safety vests while local fisherman say they cannot fish because of the pollution.

More than 700,000 refugees and migrants have made their way across the Mediterranean to Europe this year.

The majority have landed on the Greek islands closest to Turkey.