European Commission president Jean-Claude Juncker has reportedly threatened to resign unless Martin Schulz is allowed stay on as European Parliament president, beyond the 2½-year term he agreed to in 2014.
Mr Juncker told a closed-door meeting that if Mr Schulz was forced out, "then I cannot guarantee my future as commission president", according to Der Spiegel in its Saturday edition.
A commission spokeswoman didn’t deny the quote, the magazine said, but ruled out Mr Juncker’s departure.
The row over Mr Schulz’s future in Brussels has spread to Berlin, with speculation that the Social Democrat (SPD) politician could take over as German foreign minister.
The current foreign minister, Frank Walter Steinmeier, is likely to vacate the post next year after he was nominated as the ruling grand coalition’s candidate as Germany’s next president .
With less than a year to Germany’s federal election, however, Mr Schulz has reportedly insisted he is only interested in taking over as foreign minister if he can run as SPD candidate against Chancellor Angela Merkel.
On Friday, Mr Schulz denied the exclusive report in the Frankfurter Allgemeine (FAZ) daily as "so exclusive not even those involved knew about it".
The report was also dismissed by a spokesman for SPD leader Sigmar Gabriel, who has first refusal on challenging Dr Merkel.
In Brussels, Mr Schulz is coming under pressure to stand aside by the parliament’s major centre-right grouping, the European People’s Party (EPP). Several EPP candidates are said to be interested in succeeding Mr Schulz, including Irish MEP Mairead McGuinness.
With EPP officials demanding clarity from Mr Schulz on his intentions, the reported resignation threat by Mr Juncker complicates matters further.
Mr Juncker comes from the EPP but has worked closely with Mr Schulz since they both took office. If Mr Juncker has linked his future to that of Mr Schulz in the EU, it gives European leaders the option of keeping both – or neither – as they struggle with growing public anger at political elites and the consequences of globalisation.
Mr Schulz is said to have mixed feelings about entering domestic politics in Berlin after a quarter of a century shaping the European project in Brussels.
"I feel bound to this project and want to continue making my contribution," he told allies earlier this week, according to Der Spiegel.
