German Chancellor Angela Merkel said Tuesday that there was still no basis for talks on a new Greek bailout, as she arrived in Brussels for an emergency summit of eurozone leaders.

"We still do not have the basis for negotiations" for a new aid programme with the EU's bailout vehicle, the European Stability Mechanism, she told reporters ahead of the summit called in the wake of Greece's 'No' vote in a referendum on austerity.

Merkel said they would discuss how to go on, but "we will not be able to get a final picture. Though I have to say that it is not a question of weeks any more, but a question of a few days".