Preliminary information from Greece about its debt-buyback operation suggests the program went very well, a spokeswoman for Germany's finance ministry spokeswoman said on Wednesday, without giving any details.

"Finance ministers were given a preliminary evaluation which said the program went well. The troika (of international creditors) has to carry out a detailed evaluation, and on that basis the Eurogroup will decide on the payment of the next tranches," said ministry spokeswoman Marianne Kothe.

(Reporting by Stephen Brown and Gareth Jones)