"Donald Tusk made an aimless, ill-timed and pointless intervention on the refugee issue, and I don't think his proposal has any hope of being adopted," Greek Prime Minister Alexis Tsipras tweeted ahead of the two-day EU meetings starting on Thursday.
"We will not accept any phrase in the (summit) conclusions that does not refer to equal (burden) sharing," Tsipras said.
Tusk said in a pre-summit letter to leaders that mandatory relocation was "ineffective" and "highly divisive", recommending that efforts should instead be directed to securing Europe's borders.
Under a scheme introduced in 2015, asylum seekers from the frontline states of Greece and Italy were moved to other EU countries under a quota system, but Hungary, Poland and the Czech Republic have refused to take almost any.
Plans by the European Commission to introduce a permanent mechanism for refugee-sharing for any future crises have been stalled for months.