German Chancellor Angela Merkel says European Union countries cannot show only "selective solidarity" when it comes to dealing with migrants.
European Council President Donald Tusk said before the EU summit that the bloc's mandatory refugee quota system has been divisive and ineffective.
Ms Merkel, whose country took in large numbers of migrants in 2015 and 2016, said as she arrived at the summit that the basis for consultations set out by Mr Tusk is "not yet sufficient".
Ms Merkel said: "We need solidarity not just in regulating and steering migration ... on the external borders - that is good and important, but we also need internal solidarity.
"In my opinion, there cannot be selective solidarity among European (Union) member states."