TEHRAN, Young Journalists Club (YJC) - EU President Donald 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 due to fierce opposition from some member states.
EU Migration Commissioner Dimitris Avramopoulos launched a stinging attack on Tusk on Tuesday, saying that "the paper prepared by President Tusk is unacceptable, it is anti-European."
European Commission spokesman Margaritis Schinas returned to the subject on Wednesday, insisting there was "no dispute, no drama".
But Schinas said the commission, the executive arm of the EU, "firmly disagrees with the statement that relocation as an emergency response has been ineffective."
He said that over 32,000 people had been relocated under the plan, or 90 percent of those eligible. The scheme was originally meant to relocate 160,000 refugees.
Germany and Sweden lead the states backing a permanent quota system under a reform of the EU's asylum rules in the wake of the biggest refugee crisis in its history.
But many central and eastern European states are against them, promising a long night of talks on the issue on Thursday.
"We can expect a very lively and maybe controversial debate," one EU diplomat said on condition of anonymity.
Reflecting the divisions, another European diplomat said that Avramapoulos had overstepped the mark "by far" with his comments, but a third said that there had been "criticism of the balance" in Tusk's note.