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BERLIN, Oct 12 (Reuters) - The three parties that made big gains in Germany's national election aim by Friday to have a basis on which to decide whether to move to full coalition talks, the Free Democrats said on Tuesday.
The Social Democrats (SPD), who came first in last month's election, the Greens and the pro-business FDP have held exploratory talks on whether they have enough in common to form a government together.
"We will assess the results of the past few days' discussions and write down what we can do together," FDP Secretary General Volker Wissing said, adding the parties are now discussing the areas where they are the furthest apart.
Mindful of the collapse of tricky three-way coalition talks after Germany's national election four years ago, the three parties are keeping tight-lipped about talks, saying they needed to thrash out their differences in private.
The process was "very difficult" and there was no guarantee of an actual decision on Friday, but the discussions were productive, Wissing added. He declined to speculate on a coalition formation timetable beyond that.
While the Greens and the SPD are seen as ideologically close, the FDP is far from them, especially on economic and fiscal policy.
"After (the) past days of talks, I am sure we can come up with an agreement together if we work on it," SPD Secretary General Lars Klingbeil said, adding he is optimistic about the next two days of negotiations.
"We have agreed to discuss in these talks the areas where we are furthest apart," he added. "We don't have to exchange pleasantries." (Reporting by Thomas Escritt and Zuzanna Szymanska; Editing by Alison Williams)