More than 40 nations wrapped up an economic summit in the Polish capital on Friday, to the sound of a warning to the United States to work for partnership rather than domination in its relations with the expanding European Union.
"I would like to tell our American allies that no country in the world, even the most capable, is capable of tackling the global challenges as shown in Afghanistan and Iraq," Polish President Aleksander Kwasniewski told a closing session of a three-day European Economic summit.
"The European Union needs the United States, but we can see how much the US needs Europe as well," said Kwasniewski, whose country, the biggest set to join the EU as midnight rings in Saturday, was one of Washington's staunchest allies in the war which toppled Iraqi leader Saddam Hussein.
A similarly strong message came from Portuguese President Jorge Sampaio, whose country also backed Washington over Iraq, who told Washington: "Our role is not only to follow.
"Please do not repeat last year's events in relation to the Iraqi problem," he told the session.
"I'm a true believer in these relations. But I'm totally against an intellectual domination. We need to get back to the multilateral approach."
Although Sampaio, a socialist, opposed the war, the centre right Portuguese government backed it.
The EU was split in two when the United States decided to go to war in Iraq last year.
The EU's incoming, mainly ex-communist bloc members, in particular drew fire from the EU's heavyweight founding members France and Germany for siding
with Washington.
At the same time the United States has been wary of the moves by the EU to boost its own defence role, fearing it will tread on the toes of the Nato transatlantic military alliance.
German President Johannes Rau played down concerns of a conflict of interests between the two organisations at the closing summit session.
"Transatlantic relations are an important, steady element and most countries are part of both organisations, the EU and Nato," he said. "Only together the democracies of North America and Europe will be able to face up to the challenges of security," he said.
The EU was due to admit Cyprus, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia and Slovenia on Saturday.
Many believe the US hopes the arrival of 10 new members will bolster backers of close ties to Washington, at a time of serious strains in trans-Atlantic relations.
The three day economic summit, organised by the World Economic Forum, was attended by up to 20 presidents and prime ministers and hundreds of other ministers, representatives of international organisations and businessmen.
During the meeting participants expressed concerns that the EU's enlargement could leave ordinary people alienated unless it helped create jobs and fuel growth.