US Secretary of State Condoleezza Rice has called for a "new chapter" in the transatlantic alliance, in her first key foreign policy speech.
Ms Rice said ties between the US and Europe were "unbreakable"
"It is time to turn away from the disagreements of the past," she said in Paris, adding that Europe must "stand ready to work with America".
The new US secretary of state said she chose the French capital for the speech because it was a "centre of debate".
France is the sixth stop in Ms Rice's eight-nation tour.
Ms Rice's speech at the Fondation Nationale des Sciences Politiques was watched closely.
It was anticipated that she would seek to improve relations that were strained by the controversial invasion of Iraq and the aftermath of the war.
Ms Rice acknowledged that Europe and the US "have not always seen eye to eye", but said that it was "time to open a new chapter" in the relationship.
The US and Europe should move beyond "a partnership based on common threats" and focus on a partnership based upon "common opportunities, beyond the transatlantic community", she said.
"America stands ready to work with Europe on our common agenda, and Europe must stand ready to work with America."
BBC state department correspondent Jonathan Beale says Ms Rice's speech signals more cordial relations - but that Europe and the US remain wary of how the other will behave in future.
French Foreign Minister Michel Barnier reflected that wariness in what correspondents described as double-edged thanks.
He had warm words for the US secretary of state, saying, "Our two countries, dear Condi, are each other's oldest allies" - but he added, "I also think that alliance doesn't mean allegiance."
Warning to Syria
Correspondents say the choice of Paris for Ms Rice's speech is seen by many in France as a conciliatory gesture from a second Bush administration.
RICE'S SEVEN-DAY TOUR
Fri: Met UK's Tony Blair and Foreign Secretary Jack Straw in London; talks with Germany's Gerhard Schroeder in Berlin
Sat: Talks with leaders in Germany, Poland and Turkey; met Russian foreign minister in Ankara
Sun: Met Turkish government, then on to Israel to meet Ariel Sharon
Mon: Talked with Mahmoud Abbas in West Bank
Tue: Delivered speech in Paris
Wed: Talks with French ministers, then on to meet Nato and EU officials in Brussels and Luxembourg
Thurs: Returns to Washington
French judicial officials said on Tuesday that the US had agreed to repatriate the last three French detainees held at the US prison camp at Guantanamo Bay, Cuba.
Ms Rice arrived in Paris from Rome, where she held talks on Tuesday morning with Italian Foreign Minister Gianfranco Fini and the Vatican's secretary of state, Cardinal Angelo Sodano.
Speaking earlier in the Italian capital, Ms Rice said she was optimistic about the Middle East peace process, but challenged the Syrian government to back the negotiations.
She called on Syria to end its support of militant groups, and to show it did not want to be isolated.
In the French capital, Ms Rice met President Jacques Chirac and Foreign Minister Michel Barnier.
On Wednesday, she will visit Brussels and Luxembourg for talks with Nato and European Union officials.
Her trip is set to pave the way for President George W Bush's own visit to Europe later in February.