German Chancellor Angela Merkel said on Sunday that it was unclear when her conservatives would be able to wrap up coalition talks with the Social Democrats (SPD) and she expected the remaining negotiations to be tough.
"We've gathered here again today for the decisive round of negotiations. It's not yet possible to say how long it will last - We did good groundwork yesterday but there are still important issues that need to be resolved," Merkel said before heading into negotiations.
"I'm going into talks with goodwill today, but I also expect that we'll face difficult negotiations in today's session," she added.
The two camps aim to seal a deal by the end of Sunday to renew the "grand coalition" that has governed since 2013, although some politicians say they could run into Monday or Tuesday.