France said on Thursday it did not rule out joining U.S.-led air strikes on Syria, just hours after an Algerian Islamist group beheaded a French tourist in retaliation for French military action against Islamic State militants in Iraq.
France has repeatedly said it would not take part in air action in Syria where Islamic State has its power base. On Thursday it struck its first targets in almost a week since joining the United States in raids against militants in Iraq.
Paris fears that strikes against Islamic State in Syria would leave a void that only Syrian President Bashar al-Assad's forces could fill, making it difficult for rebels to counter the more organised Syrian army.
But the killing of Herve Gourdel, who was beheaded in Algeria hours after an ultimatum was given to France to end its Iraqi mission, appeared to toughen Paris' resolve.
"The opportunity is not there today. We have an important task in Iraq. We will see in the coming days how the situation evolves," Defence Minister Jean-Yves Le Drian told RTL radio.
Pressed further on whether air strikes on Syria were a possibility in the future, Le Drian said: "The question is on the table".
After a war cabinet meeting on Thursday, the French presidency said it was ready to do more to fight Islamic State.
"France is ready to support all states that ask for it so that necessary measures can be put in place quickly," it said.
President Francois Hollande, who has previously sanctioned weapons deliveries to rebels, on Wednesday met the President of the Syrian National Coalition at the U.N. General Assembly.
He said the rebels were the only legitimate representative of the Syrian people, dismissing Assad once again.
"Daesh (Islamic State) is continuing its acts of terror in Iraq. In Syria, tens of thousands of people have had to flee a new offensive," the presidency statement said.
"In the framework of the coalition, France will continue to support Iraqi authorities ... it will also reinforce support to the Syrian opposition currently fighting the jihadi groups."
U.S. and coalition planes pounded Islamic State positions in Syria on Wednesday, but the strikes did not halt the fighters' advance in a Kurdish area where fleeing refugees told of villages burnt and captives beheaded.
Until recently, French officials have said the question of striking Syria was hypothetical given they had not been asked to do so by coalition partners, and that its efforts would centre on providing weapons and training to Syrian rebels.
However, this week there has been a slight shift in the French position. Ahead of the start of U.S, and Arab strikes in Syria on Monday, Foreign Minister Laurent Fabius said Paris no longer saw any legal barrier to Syrian air strikes.
Speaking on France Info radio on Thursday, Fabius said the question of action in Syria should weigh the two enemies there.
"Strikes have to be carried out, which the Americans are doing, but we need to denounce Assad who remains a dictator."
Gourdel's killing appeared to unite politicians, religious leaders and the public on Thursday with calls for greater action against Islamic State, which has specifically urged its followers to attack French citizens.
That has prompted Paris to warn embassies across the Middle East and Africa of an increased threat. The presidency said on Thursday new preventive measures against the risk of terrorism would be taken at public venues and on transport.
To commemorate Gourdel, the government said flags would be kept at half-mast for three days. Minutes of silence and vigils were held across the country.
The Muslim Council in France called for a rally on Friday at the Paris Grand Mosque against Islamic State.
"The terrorists want to scare us," Fabius said. "They are practicing a bloody blackmail which we can't give into. We will not surrender to it."