German Chancellor Angela Merkel's coalition is under threat because of a major row over migrants with her interior minister, the CSU's Horst Seehofer. He wants German border police to turn back all asylum seekers without the correct documentation at the border.
Merkel's CDU party have backed her view that a new deal should be agreed at EU level. She thinks going it alone would further damage relations with Italy and Greece, who have carried the greatest burden of refugees since the crisis began.
Typically, migrants enter Europe through Italy, cross over to Austria and attempt to get into Germany.
In the future, Seehofer wants to block them at the German border, which would leave Austria to deal with them.
According to current European law, migrants hoping to apply for asylum must do so in the first country they enter.
As a minister, Seehofer could take the decision alone but that would risk fracturing the coalition and lead to early elections. The crisis also highlights ongoing public concern over immigration and the impact of Merkel's liberal 2015 strategy.
"We have always run up against the problem of ‘yes, let’s keep them from coming into Europe, but let’s not watch people die in the Mediterranean," explained analyst and author Christopher Dickey. "And people have continued to come and continued to die. It is an extremely difficult situation. You have got Italy and France divided, you have got now Spain playing a different role than it used to play because it has a new government, and then you have Poland and Hungary, who do not want any migrants at all in their country, and they are completely unsympathetic to countries that say there should be shared responsibility throughout the European Union."
The Dublin treaty on migrants can be interpreted in different ways, but as well as the law, Merkel will have to consider public opinion and politics.