The 16 heads of government and state are responding to alarm about growing rifts not only among the EU's 28 members but also within the German government itself, the bloc's most powerful.
As tensions rise between Rome and Paris as well as Rome and Berlin, the top-level talks are designed to help clear the heavy air for a previously scheduled full summit of all EU leaders on Thursday and Friday. But German Chancellor Angela Merkel has conceded "no solution will be reached" on the overall migration issue at either summit.
This is despite a sharp decrease in migrant arrivals since their peak in 2015, when more than one million Syrian asylum-seekers and others entered the bloc.
Political developments in Italy, a major migrant landing point, and in wealthy Germany, their top destination, have brought the EU's political crisis back.
Since assuming office several weeks ago, Italy's new populist government has refused to admit foreign-flagged rescue ships packed with hundreds of migrants. After turning away the Aquarius, which later docked in Spain, Rome vowed Saturday to block the Lifeline, a German charity vessel with more than 230 people aboard.
Reflecting popular anger over the failure of EU member states for years to shoulder more of the migrant burden, Rome has pledged not to take in one more asylum-seeker.
Italy's stance has raised tension both with Germany and within Merkel's coalition government, with EU diplomats saying the mini-summit is to help "save" the chancellor.
With a populist backlash over her initial open-door policy toward asylum-seekers, Merkel emerged weakened in recent elections.
Now facing a political crisis, Merkel's new hardline interior minister Horst Seehofer has given her until the end of June to find a European deal to curb new arrivals. If that fails, he vowed to order border police to turn back migrants, which means many will likely have to return to Italy.
Merkel also got Italian Prime Minister Giuseppe Conte to attend the mini-summit by telling him pre-written conclusions had been withdrawn, Italian officials said.
Newspaper headline: Heads of state to deal with political divide