[Migrants who will be returned to Turkey demonstrate inside the Moria registration centre on the Greek island of Lesbos]The tension is palpable on Greece's islands, where about 8,000 asylum seekers feel stranded by a European Union deal with Turkey to stem the arrival of refugees and other migrants on European shores from Syria, Iraq, Afghanistan and beyond. The deal, hailed a success by its European architects, prevents migrants from going beyond Greece - or even its islands - in their search for a new home in Europe, until their asylum claims are processed and those rejected are sent back to Turkey, from where they arrived. In clashes on Lesbos the night of June 1-2, families with young children had to flee and spend the night in nearby fields or Mytilene town, several kilometres away, Amnesty International said.