PARIS -- The two most vocal advocates of an international response to a chemical weapons attack in Syria teamed up on Saturday when Secretary of State John Kerry and his French counterpart made an unusual joint appeal for military action.
"France and the United States stand together," said Laurent Fabius, the French foreign minister, who argued that a punishing military strike was needed to redraw the red line against the use of chemical weapons.
Mr. Kerry reached back to President John F. Kennedy's meetings with President Charles de Gaulle and sought to touch a chord with wary Europeans over the need to stand up to the "slaughter" of civilians by delivering much of his presentation in fluent French.
France has displaced Britain as the United States' main military ally if force is to be used against the Syrian government.
But Mr. Kerry and Mr. Fabius, who each confront a skeptical public at home, need each other politically as well. France has been Exhibit A in the State Department's campaign to demonstrate that it has managed to mobilize some international support.
French officials, for their part, have made clear that they do not want to go it alone against Syria.
The events that unfolded on Saturday, however, indicated that the next phase of the American and French partnership on Syria will require more coordination.
In an effort to obtain broader backing for a military operation from European nations, France's president, François Hollande, said Friday that his government would not act militarily before United Nations inspectors presented their findings about the Aug. 21 chemical weapons attack near Damascus, Syria's capital.
The move was intended to secure a measure of support from Germany, Italy and other European nations, which are concerned that action will be taken without the approval of the United Nations Security Council because of the threat of a Russian veto. And it enabled Mr. Hollande to make the point that there would be some sort of United Nations process before the use of force.
After Mr. Hollande's remarks, the European Union issued a statement on Saturday at a meeting in Lithuania calling for a "clear and strong response," endorsing his decision and expressing hope that a "preliminary" version of the report by the United Nations inspectors would be released "as soon as possible."
The statement, which was read by Catherine Ashton, the European Union's chief foreign policy official, papered over some of the lingering divisions in the European Union's ranks.
The statement urged the Security Council to "fulfill its responsibilities" but pointedly did not call for an attack or say that the Council's approval was required before a military strike could be carried out.
Still, the European Union's move enabled Germany and France to narrow the gaps between their positions.
On Saturday, Germany indicated that it would support an international response in Syria, with Foreign Minister Guido Westerwelle saying in Vilnius, Lithuania, that Berlin had wanted to wait for European foreign ministers to take a common stand before making its decision.
But while the maneuvering preserved the appearance of European unity, it posed some potential complications for the Obama administration.
Since the mandate of the United Nations inspectors is limited to establishing whether a chemical attack took place, and not who carried it out, the Obama administration has repeatedly asserted that the United Nations evaluation is irrelevant.
But since the administration is also eager to have French participation in any attack, it also has a powerful incentive to accept Mr. Hollande's approach, especially if it would not greatly delay an American strike for which President Obama has decided to seek Congressional approval.
Senate and House members return from their recess on Monday, when debate on the issue is expected to pick up. Mr. Obama is scheduled to address the nation Tuesday night about Syria.
Mr. Fabius suggested on Saturday that an arrangement might be worked out to protect the interests of all sides.
He said Ban Ki-moon, the United Nations secretary general, had assured him that the inspectors' assessment would be submitted very soon.
Mr. Fabius made it clear that he expected the report to be presented before October, and a Western European official who asked not to be named, because he was privy to private diplomatic communications, said it might be ready by next Sunday or soon after.
Such a schedule would enable the United Nations to claim that the work of its inspectors was relevant. It would enable European governments to tell their constituents that there had been United Nations involvement before military action, and it would not appear to tie the Americans' hands.
Mr. Kerry declined to comment on the Europeans' insistence that any military action follow the submission of the inspectors' preliminary report, adding that he would take up the question with Mr. Obama and top officials after he returned to Washington on Monday.
But with an uphill battle to win Congressional support and Mr. Obama receiving less backing than he would have wished during the recent Group of 20 summit meeting, the White House may be ready to embrace Mr. Hollande's strategy.
"The president has given up no right of decision in respect to what he will do," said Mr. Kerry, who nonetheless added that he was encouraged by the "very powerful statement" made by the European Union.
Suzanne Daley contributed reporting from Paris.
This article originally appeared in The New York Times.