Europe is in danger of falling behind in the global race for economic success unless it reforms, Prime Minister David Cameron has said.
Mr Cameron was speaking as he arrived for a meeting with anti-federalist party leaders in Brussels ahead of a European Council summit.
The summit of heads of government from the 27 member states will discuss an interim plan for economic and monetary union within the eurozone, designed to bring an end to the crisis in the single currency.
Speaking to reporters as he arrived in the Belgian capital, Mr Cameron said the EU needed to cut costs, regulations and bureaucracy and sign trade deals with major markets such as the US and Japan.
He said that, most importantly, it had to complete the European single market to give companies from member states fuller access to the biggest trading bloc in the world.
Mr Cameron, who has said that both the UK and Europe are engaged in a "global race" with emerging economic giants for future prosperity, warned: "There is a danger of the European countries and the European Union falling behind."
Thursday's summit will receive an interim report drawn up by the presidents of the European Council, European Commission, European Central Bank and Euro Group on the way forward for the single currency.
Proposals involve banking union for the eurozone area, with a single supervisory authority overseeing financial institutions in the 17 countries which use the single currency. The proposals involve significant moves towards pooling the sovereignty of the eurozone nations and discussions are likely to be protracted, with no decisions expected before leaders leave Brussels on Friday afternoon.
The Prime Minister is expected to say that, in addition to establishing a single market for the digital economy, concrete measures are needed to complete other unfinished and potentially lucrative parts of the single market policy, from opening up services to bearing down on unnecessary rules and regulations.
Mr Cameron will continue to endorse closer 17-country eurozone integration as long as the planned measures do not hamper the progress of the 27-nation single market. But behind the scenes, divisions are deepening within the eurozone on the balance between austerity and growth.