[File photo of refugees walk along a beach before trying to travel to the Greek island of Chios from the western Turkish coastal town of Cesme]GENEVA (Reuters) - The United Nations called on Friday for safeguards to be in place before refugees are returned to Turkey under an agreement with the European Union, while warning that conditions in Greece are deteriorating. "This is in light of continued serious gaps in both countries," spokeswoman Melissa Fleming of the U.N. High Commissioner for Refugees (UNHCR) told a Geneva news briefing. Conditions on the islands of Lesbos and Samos - where three people were stabbed in rioting on Thursday night - and at the Athens port of Piraeus and Eidomeni at the border with Macedonia are worsening. ...