ROME, Oct 29: European Union leaders on Friday signed a landmark new treaty for the 25 nation bloc but remained in discord over the future line-up of the European Commission.

"Today's proceedings mark a historic date," said Italian Prime Minister Silvio Berlusconi as EU presidents and premiers put their names on the new constitution. The treaty was signed at a solemn ceremony on Rome's Capitoline Hill, site of the 1957 signature of the bloc's original founding treaty.

"It is a constitution which defines our shared European values and aspirations," said Irish Prime Minister Bertie Ahern who helped steer treaty talks for a part of the difficult two-year negotiating process.

Others referred to the EU's birth out of the rubbles of two World Wars and its latest landmark enlargement to bring 10 mainly former communist nations of Eastern Europe into the bloc.

Specifically, the constitution aims to improve decision-making in the expanded Union and give the bloc its first-ever foreign minister. The aim is to make the EU more democratic, efficient and more powerful on the global stage.

Turning the constitution into reality poses a challenge, however. EU governments have two years to do this, either through public referendums - expected to be held in at least eight states - or approval by national parliaments.

"The signing does not mean we have crossed the finishing line," said outgoing Commission chief Romano Prodi, adding that governments now needed to persuade Europeans to vote for the new deal.

Many fear that given current public disenchantment with the EU - as witnessed in the low voter turnout in June elections to the European Parliament - securing public support for the treaty will be difficult.

Already celebrations of the new constitution come amid one of the worst institutional crisis facing the EU following this week's unprecedented standoff between the European Commission and the EU parliament.

Faced with the prospect of a parliamentary veto over the men and women who will run the bloc's executive over the next five years, incoming Commission chief Jose Manuel Barroso decided on Oct 27 to postpone an assembly vote on his new team.