Greece's debt crisis cannot be solved without a write-down on Greek debt, and this would likely have to be larger than the write-down considered this Summer, German Finance Minister Wolfgang Schaeuble told German broadcaster ARD on Sunday.

A lasting solution to the Greek debt crisis is not possible without a debt write-down, and this will likely have to be higher than that considered in the Summer. The details are being discussed now. They don't all have to be ready by the EU summit but the principles must be clear, Schaeuble said.

European Union leaders will gather for a summit in Brussels on October 23. France and Germany have said they will present a crisis resolution plan in time for the summit.

(Reporting by Sabine Siebold)

Germany Down