German Chancellor Angela Merkel has warned European Union leaders that they will make "a historic failure" if they do not agree on a time table for the adoption of an EU constitution.
Ms. Merkel spoke in Berlin at the main celebration of the 50th anniversary of the bloc's founding Treaty of Rome. Commemorations are also held in Rome, Brussels and Budapest.
The Ode To Joy from Beethoven's 9th Symphony, the European Union anthem, was the musical highlight at an otherwise solemn ceremony in Germany's capital Berlin.
Leaders of the 27 EU member states recalled that a half century ago in the aftermath of World War Two the block's founding fathers signed The Treaty of Rome, which later led to the establishment of the European Union.
The main ceremony was held in Berlin because Germany holds the EU rotating presidency.
German Chancellor Angela Merkel, who grew up in what was then communist East Germany, appeared joyful that the ceremony could be held in Berlin, which until German re-unification in 1990 was a symbol of Europe's division.
Ms. Merkel said she regrets the European Union remains divided over adopting a constitution. She vowed Germany would push for renewal of the constitutional treaty that was blocked by Dutch and French 'no' votes in referendums in 2005.
Ms. Merkel urged fellow EU leaders to agree on a timetable for the bloc's constitution by the end of June.
"I am working to ensure that a roadmap for this can be adopted at the close of Germany's EU presidency, and I am counting on your support," Ms. Merkel said. "I am certain that it is not only in the interest of Europe, but also of the individual member states and the citizens of the Europe, that this process be brought to a successful conclusion. Ms. Merkel said not to do so would be an historic failure
Ms. Merkel said a constitution is needed for the bloc at a time when it plays a more global role, both economically and in its campaign defending human rights, including in nearby Belarus and further away in Sudan and Zimbabwe.
At the same time, pro-democracy activists aimed to rally thousands of supporters in he capital of Belarus, Minsk, hoping to increase the momentum for change in the authoritarian ex-Soviet republic. Last year's annual protest march on what the opposition calls Freedom Day - the anniversary of the 1918 declaration of the first Belarusian state - ended with police clubbing defiant demonstrators and detaining hundreds.
In Berlin, Merkel and other officials signed The Berlin Declaration, which recalls the Treaty of Rome and spells out the future role of the European Union.
It says it remains "committed to the peaceful resolution of conflicts in the world" and wants to ensure "that people do not become victims of war, terrorism and violence." The declaration also pledges to take a leading role to "drive back poverty, hunger and disease."
European Parliament President Hans-Gert Poettering said the Berlin Declaration is a good base for future negotiations on the constitution.
"The text says what we have to do in the future. And the text commits ourselves to do everything to reform the European Union before the next European elections in June 2009. Some countries have a problem with the word constitution, which I personally and the European Parliament like very much. But the most decisive is that we can keep the substance of the Constitutional Treaty. If we do so and if we can find an agreement on the substance, that is the most important."
Public-opinion polls show that nearly half of all European Union citizens believe the institution is far removed from their everyday lives.
Hungary is among the most skeptical countries with polls showing that just about 39 % of the population believes EU membership is beneficial. Commentators suggest it will take more than this weekend's EU sponsored concerts in Brussels and night club or museum visits in Berlin, to change attitudes among Europeans.