German Chancellor Angela Merkel and France's Francois Hollande will likely meet next week to finalise plans for a more integrated eurozone as the threat of a British exit from the EU looms, European sources said.
The Berlin meeting, which will also include European Commission head Jean-Claude Juncker, was "almost certain", the sources said, in a move that will cause tremors in a eurosceptic London suspicious of a two-speed Europe dividing euro and non-euro nations.
The official subject of the discussion will be a joint Franco-German roadmap for the future of the 19-member single currency in response to a request by Juncker for member states to brainstorm a better governance for the eurozone hit hard by the debt crisis.
But the talks land just weeks after British premier David Cameron won a second term in office on the promise of an in-out EU referendum by 2017, amid speculation that British voters will vote against staying in the bloc.
"The deepening of the European economic and monetary union is a process that is in its final stages while Cameron is only beginning his," a European source told AFP in confirming the Berlin meeting.
Cameron argues that the EU should be retreating from further integration instead of embracing it, and that Europe risks a no vote in Britain by failing to change.
But the Berlin and Paris proposal for the summit, which was seen by AFP, not only mentions tightening ties in the eurozone, but doing so without changing the existing treaties that govern the EU.
But re-opening the treaties in order to reform them is a key demand of non-euro Britain as it heads to a referendum.
Kickstarting his own diplomatic efforts to secure EU reforms, Cameron hosted Juncker at his country residence on Monday.
"The Prime Minister underlined that the British people are not happy with the status quo and believe that the EU needs to change in order to better address their concerns," a spokesman for Cameron's office said after the talks.