EU ambassadors in Brussels sat together until after midnight on Monday and will continue on Tuesday evening to try to clear up all the question marks surrounding the EU Commission's proposed billion-euro loan.
Belgium, which physically houses most of the frozen Russian assets that the EU wants to use, is still not satisfied with the guarantees promised that everyone will share the risks.
There will be no agreement before the summit, an EU diplomat tells the news site Politico Europe.
The goal is still to get Belgium to say yes, rather than to push through a decision against their will.
It is clear that it is important to try to accommodate many of the views that Belgium has, says EU Minister Jessica Rosencrantz (M), who is discussing the loan with her colleagues in Brussels on Tuesday.
