US President Barack Obama has urged the EU to accept Turkey as a full member of the 27-nation bloc, a move immediately rejected by France's Nicolas Sarkozy.
The disagreement is a rare outward sign of divergence at an EU-US summit stage-managed to relaunch transatlantic ties that were strained under the Bush administration.
'The United States and Europe must approach Muslims as our friends, neighbours and partners in fighting injustice, intolerance and violence, forging a relationship based on mutual respect and mutual interests,' Mr Obama told the summit.
'Moving forward towards Turkish membership in the EU would be an important signal of your (EU) commitment to this agenda and ensure that we continue to anchor Turkey firmly in Europe,' he told EU leaders.
Turkey has long been seeking to join the union, and Mr Obama's comments were a reaffirmation of US support for that goal.
But there is resistance among EU states such as Germany and France to its membership, including among ruling conservatives.
Mr Sarkozy said it was up to the EU member states to decide on Turkish entry and reiterated his opposition.
'I have always been opposed to this entry,' he told France's TF1 television.
'I still am and I think I can say that the immense majority of member states shares the position of France.
'Turkey is a very great country, an ally of Europe, an ally of the United States. It will stay a privileged partner. My position hasn't changed and it won't change.'
Turkish entry talks with the EU have been held up by European concerns over human rights, a perceived lack of progress on reforms, and by a long territorial dispute with EU member Cyprus.