German Chancellor Angela Merkel and Social Democrat leader Martin Schulz in a TV debate ahead of the German election | Omer Messinger/Getty Images German Social Democrats open to talks with Merkel The SPD leadership previously refused to entertain the possibility of governing with the conservatives again.

BERLIN — Germany's Social Democrats have dropped their hard refusal to consider governing with Angela Merkel’s conservatives.

In a meeting that lasted through most of the night, party leaders decided to help resolve an impasse that has left Germany without a clear coalition option for the first time in its post-war history.

“The SPD is deeply convinced there should be discussions,” Hubertus Heil, the party’s general secretary, told reporters after the marathon session Friday. “The SPD will not refuse to talk.”

Heil's statement means the party is open to discussing at least two possible options with Merkel — reprising its role of the past four years as her junior partner in government or supporting a minority administration.

German President Frank-Walter Steinmeier has invited Merkel, SPD leader Martin Schulz and Horst Seehofer, the chairman of the Bavarian sister party of the chancellor's Christian Democrats, for talks next Thursday, Spiegel reported.

Schulz said on Twitter that if the talks led to the SPD being involved in government, the decision would be put to a vote among party members.

"In a dramatic appeal, the president called on to the parties to hold talks," Schulz said. "We will not reject it."

The SPD leadership previously refused to entertain the possibility of another “grand coalition” with the conservatives. Schulz reiterated that position on Monday after talks to form a three-way government between the conservatives, liberals and Greens collapsed.

Since then, he has come under intense pressure from both inside and outside the SPD to reconsider in order to avoid a new election.

Heil denied reports that Schulz had come under pressure to resign.

In addition to joining another coalition, he said the SPD could agree to “tolerate” a Merkel-led minority government from the opposition, an option gaining currency in Berlin.

Jens Spahn, the deputy finance minister and a leading figure in Merkel's Christian Democrats (CDU), said during a panel discussion in Berlin Thursday that he “supports trying a minority government" if talks with the SPD over renewing the "grand coalition" of the last four years fail.

Another high-ranking CDU official, from the conservative benches in the Bundestag, said such a solution, though inherently unstable, was preferable to calling a snap election which would prolong the crisis.

From the ranks of the SPD, which would provide external support for the conservative chancellor without re-joining her government as the junior coalition partner, one party official described such an arrangement as "far from ideal, but the lesser evil.” A minority government would avoid a snap election and also avoid angering grassroots SPD supporters who deeply dislike the idea of another grand coalition, the official said.

However, some SPD members are wary of shoring up a Merkel-led minority administration, fearing they would be blamed for unpopular government policies but would not have any of the advantages of being in power.

"The SPD would bear responsibility for policies that it really hadn't been involved in formulating," Christian Ude, an SPD former mayor of Munich, told German radio. "No one has been able to explain to me how that's better than being in a coalition."

In a letter to party leaders, two SPD veterans threw another possibility into the mix on Thursday evening — a coalition between the conservatives, the Social Democrats and the Greens.

Such an alliance would not be necessary in arithmetic terms, as the SPD and the conservatives alone would have a majority. But Wolfgang Thierse, a former president of parliament, and Gesine Schwan, chair of the party's basic values commission, said it would mean a greater focus focusing on social justice and a new impetus for European policy.

The Greens, however, quickly expressed skepticism about a "Kenya" coalition — so-called because the colors of the parties match those of the East African nation's flag.

"I don't really understand the added value of Kenya," Greens' co-leader Cem Özdemir told broadcaster SWR Aktuell. "The Greens would be there as an addition but they wouldn't really be needed."

This article has been updated with additional information.