US and French defense chiefs discussed the possibility of France taking part in the American-led air war against Islamic State jihadists in Syria, Defense Secretary Chuck Hagel said.
But his French counterpart, Jean-Yves Le Drian, would not confirm or deny that the subject came up during his talks at the Pentagon.
"Yes, we did discuss possibilities of France's involvement in Syria," Hagel said at a joint news conference.
The talks in Washington came as IS militants in Syria closed in on a key town near the Turkish border, Kobane, despite US air strikes in support of besieged Kurdish fighters.
France is one of five European countries that have committed aircraft to the campaign in Iraq but none of them are involved in the US-led air attacks on IS in neighboring Syria. Five Arab countries are participating in the American-led bombing raids there.
France has provided weapons to Syrian rebels fighting both the Damascus regime and the IS group.
Le Drian said France was participating in air strikes against IS in Iraq because Baghdad had made a formal request under the UN charter.
"France is there because of that request. And we are in the coalition because of that request," he said.
Pressed again on the Syria issue by French journalists after the news conference, Le Drian said: "I cannot answer a question that was not asked."
The minister has previously suggested that Paris had not ruled out an eventual role in the Syria campaign.
- A 'difficult and long' effort -
On Wednesday, the French military said it would deploy three more fighter jets and a naval ship to the Middle East to bolster support for Iraqi forces fighting the IS militants.
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Echoing warnings from President Barack Obama and top commanders, Hagel said the fight against the Sunni jihadists would deliver no easy victories.
"This effort against ISIL (IS group) with our coalition partners, both in Syria and Iraq, is going to be difficult and it's going to be long.
"And there were no misconceptions when we started this that there would be any quick finish," Hagel said.
Asked about the timeline for training Iraqi forces, Hagel said he didn't know how long it will take.
Le Drian said both countries had "excellent cooperation" between their spy agencies but sidestepped a question as to whether US missile strikes on Al-Qaeda militants near Aleppo on September 23 were based on French intelligence.
Both Hagel and Le Drian welcomed a vote by Turkey's parliament approving military action against the IS group.
Turkey has often proposed creating a "buffer zone" along its border with Syria to protect civilians and stem the flow of refugees.
Hagel, however, said the US government was not currently considering carving out a buffer zone in northern Syria, but remained open to discussing various "options" with the Turkish government.
"We continue to talk with Turkish government about many options but there are no plans for that option right now," Hagel said.
The US military's top officer, General Martin Dempsey, has said a safe zone would require round-the-clock air patrols and a substantial ground force to enforce it.
In his opening remarks, Le Drian focused mainly on the threat posed by Islamist extremists across the Sahel region in Africa.
The minister thanked Hagel for America's assistance to French forces in Mali and elsewhere in Africa, where the US military has provided surveillance drones, transport and refueling aircraft.
Washington planned to continue to aid France in its efforts against violent extremism in the Sahel, Hagel said.