United Nations Secretary General Ban Ki-moon called on Saturday for countries to do more to help cope with Europe's migrant crisis, saying Greece could not manage on its own. Speaking in Athens before heading to the Greek island of Lesbos, the gateway into Europe for nearly a million people last year, Ban said Greece had shown "remarkable solidarity and compassion" in dealing with the hundreds of thousands of migrants fleeing war, despite its economic hardship. "Greece should not be left alone to address this challenge on its own," Ban told reporters after meeting Prime Minister Alexis Tsipras.