David Cameron and German Chancellor Angela Merkel have agreed to work together to make the EU more competitive and flexible, Downing Street said today.
Following talks at Ms Merkel's guest residence at Schloss Meseberg, Number 10 said the leaders also agreed that the union should be prepared to make an "ambitious offer" in trade talks with the US.
The Prime Minister used his overnight stay in the Brandenburg countryside to set out his plans to renegotiate Britain's relationship with Europe, but the Downing Street statement offered no clue as to how they were received.
Ms Merkel is anxious that Britain should remain in the EU and has made no secret of her concerns about Mr Cameron's plan to stage a referendum on continuing membership if the Conservatives win the next General Election in 2015.
The Prime Minister and German Chancellor Merkel held talks this morning with their respective teams at the Chancellor's guest residence in Meseberg.
A Downing Street spokesperson said:
"On the EU, the PM set out his approach to European reform, following on from his speech in January. They agreed on the urgent need to make Europe more competitive and flexible and talked about ways to achieve this.
"They both want to see faster progress on trade deals between the EU and the rest of the world. And they agreed that the EU should be prepared to put an ambitious offer on the table for EU-US negotiations which we want to get underway this summer."
The Prime Minister is embarking on the start of a series of talks with EU leaders this week as he aims to put forward his agenda for Europe.
Today, he will make his first official visit to Madrid for bilateral talks with Spain's prime minister Mariano Rajoy before travelling to Paris for a working dinner with French president Francois Hollande.
He will also meet with German chancellor Angela Merkel later this week.
David Cameron insists that EU reform is "not about cherry-picking" rules as he calls for treaty changes that Europe "can benefit from".
In a statement in newspapers in France, Germany, Italy, Spain and Poland, he said:
We are a major European power, a major European player. But do we think that the European Union has sometimes overreached itself with directives and interventions and interferences? Yes, it has. And that needs to change.
There are some reforms I think we need to make. Already we're starting to make some of them.
The agenda of the speech is change that all of Europe can benefit from. It is a more competitive, open, flexible Europe for all countries of Europe. And the second thing is that - you know, this is not about cherry-picking, but to argue as some do that you can't have a flexible Europe is wrong.
We can have a flexible Europe where we don't all have to do the same things in the same way at the same time.
I'm sure there will be treaty change. I'm absolutely convinced that there will be the need to reopen at some stage these treaties, not least to solve the problem of the eurozone.
The eurozone in my view needs to have further treaty change, and just as eurozone countries will argue that it's necessary to have treaty change, I think it's perfectly legitimate to argue that non-eurozone countries might need to have treaty changes that suit them."