Speaking on a visit to Lebanon, Merkel said that "we know that no solution will be reached on Thursday and Friday at the level of the 28 member states… on the overall issue of migration".
Instead, she said, "bilateral, trilateral and multilateral" deals must be reached to tackle the issue – a message echoed almost word for word by her spokeswoman Ulrike Demmer at a Berlin press conference.
The comments came after Italy's new coalition of far-right and anti-establishment parties made clear it does not want to take in more migrants, and after several eastern European states said they would stay away from preliminary talks on the issue Sunday.
Italy's far-right interior minister Matteo Salvini reiterated in comments to German news weekly Der Spiegel that "we cannot take in one more person. On the contrary: we want to send away a few."
Merkel, after allowing more than one million asylum seekers into Germany since 2015, has faced a strong domestic backlash that has now turned into a government crisis, just over 100 days into her fourth term.
Her hardline Interior Minister Horst Seehofer has given her an ultimatum till the end of the month to reach EU deals allowing Germany to turn back asylum seekers already registered in another member country.
After that, he has vowed to defy her by ordering German border police to turn back those migrants, setting the stage for a showdown that could end Merkel's fragile coalition government.
Since then, European Commission chief Jean-Claude Juncker has called a mini-summit of member states most affected by migration in Brussels on Sunday, at the urging of Berlin.
But Merkel and Demmer also lowered expectations for those talks, stressing they are merely "a working meeting".
They also said it would not agree on a joint statement — contrary to earlier German press reports of a tough "draft communique" in the works that had sparked irritation in Rome.
"Sunday will be a first exchange between interested and affected member states, no more and no less," Demmer said, adding that it would discuss "all problems of migration, be it secondary or primary migration".
"And then we will see whether bilateral, trilateral or multilateral agreements can be reached, because right now there won't be a quick pan-European solution."