Updated

Leaders of Germany's center-left Social Democrats agreed Friday to enter exploratory talks on joining or supporting a new government under Chancellor Angela Merkel, moving unprecedentedly long efforts to form a new administration a small step forward.

Merkel's conservative Union bloc and the Social Democrats have governed Germany together for the past four years in a "grand coalition" of the country's biggest parties. The Social Democrats initially said they would go into opposition after a disastrous election result in September.

The party reluctantly reconsidered after Merkel's talks with two smaller parties collapsed last month, but party leader Martin Schulz — Merkel's defeated challenger in September — is treading carefully to avoid alienating a membership that is deeply suspicious of another coalition.

If the Social Democrats don't enter a coalition with Merkel's bloc, the only possibilities would be an unprecedented minority government led by Merkel or a new election. President Frank-Walter Steinmeier, who alone has the power to dissolve parliament, has made it clear he doesn't want a new election.

While Merkel's bloc wants a coalition, Schulz indicated the exploratory talks will also consider the possibility of a looser arrangement that still would allow a Merkel-led government to be formed.

"Whether the talks will lead to the formation of a government is open," he said Friday. "I must repeat, and we mean this very seriously: in opening these exploratory talks, we have made no decision on a particular form of putting together a government."

An initial phase of exploratory talks likely will be held during the first two weeks of January, Schulz said. A party congress to decide what happens next — approving the possible opening of formal coalition talks, for example — has been penciled in for Jan. 14 but could be delayed, he said.

Schulz has already promised a vote by the full party membership on any coalition deal.

That means Germany is on course easily to beat its previous record of 86 days — set in 2013 — for the time from an election to the swearing-in of a new government.