France is seeking a reaction with "force" if a massacre in Syria involving chemical weapons is confirmed, French Foreign Minister Laurent Fabius said Thursday, although he ruled out the use of ground troops.

France is seeking a reaction with "force" if a massacre in Syria involving chemical weapons is confirmed, French Foreign Minister Laurent Fabius said Thursday, although he ruled out the use of ground troops.

"If it is proven, France's position is that there must be a reaction, a reaction that could take the form of a reaction with force," Fabius said.

"There are possibilities for responding," he added without elaborating.

In June, Fabius had raised the possibility of using military force against chemical arms production centers after France confirmed that Damascus had resorted to such weapons.

But on Thursday the foreign minister said there was "no question" of sending in ground troops, adding "it's impossible."

If Wednesday's attack is confirmed, "I believe it cannot go without a reaction from those who believe in international legality," Fabius said.

"If the Security Council cannot take a decision, at that moment decisions must be taken in another way. How? I would not go further," he said.

UN Security Council members are seeking "clarity" on the suspected chemical weapons attack.

But diplomats said the council did not adopt a formal declaration because of opposition from Russia and China, which have for the last two years blocked any condemnation of their ally in Damascus.

"The Russians must assume their responsibilities," Fabius said.

"We are in a phase where it must be believed that the Security Council members are consistent. All said that chemical weapons should not be used.

They all signed an international accord which bans their use, including the Russians," he said.