European Union leaders have concluded a summit meeting in Greece by welcoming a draft constitution as the basis for future negotiations on power sharing between member states and the European institutions in Brussels. The leaders also endorsed a new European security strategy designed to give Europe worldwide political influence to match its considerable economic clout.

The leaders hailed the draft of the EU's first-ever constitution, calling it an important step forward in Europe's unification. But some governments made it clear they have problems with parts of the text, especially those that would restrict the use of the veto on policy decisions, as well as the document's failure to mention God or Christianity.

The draft's fate lies in the hands of delegates to an inter-government conference that will convene in October to fine tune the document. Diplomats expect hard bargaining over key sections of the text.

The leaders also voiced support for a new EU strategy paper that says good relations between Europe and the United States are irreplaceable, despite the severe strains resulting from transatlantic bickering over the Iraq War.

The paper's author, EU foreign policy chief Javier Solana, says the bloc wants to work on pressing international issues, like weapons of mass destruction, in solid partnership with the United States.

"Of course, we would like very much to discuss these ideas with our American friends," he said. "We are going to find many, many points of contact, many, many points of agreement. And I hope we will find not very many of disagreement."

Mr. Solana, backing U.S. warnings, called Friday on the militant Palestinian group Hamas and similar organizations to declare an immediate cease-fire and halt all terrorist activity or face a crackdown on its sources of funding.

"We are ready, if these organizations are not willing to cooperate in a constructive manner for a cease-fire, to take some action, particularly on the money and the financial support of these organizations," he said.

The EU also issued warnings to Iran and North Korea to cooperate with international nuclear inspectors so as to dispel fears that they are developing nuclear weapons.

Although most EU leaders have already gone home, some are staying on Saturday to meet with their counterparts from five Balkan countries that are seeking eventual membership in the bloc.