LONDON (Reuters) - U.S. Secretary of State John Kerry said on Thursday he had seen raw data suggesting Syrian government forces had used chlorine gas in the country's civil war, but added it had not been verified.
French Foreign Minister Laurent Fabius has said Syria may have used chemical weapons involving chlorine in 14 attacks in recent months.
"I have seen the raw data that suggests that there may have been, as France has suggested, a number of instances in which chlorine has been used in the conduct of war," Kerry told reporters in London.
"If it has, and it could be proven, then that would be against the agreements of the chemical weapons treaty and against the weapons convention that Syria has signed up to."
Kerry, who earlier met foreign ministers from European Union and Gulf Arab countries that are opposed to Syrian President Bashar al-Assad, said the data had not been verified.
"It has been made clear by President Obama and others that use would result in consequences," Kerry said, adding: "We're not going to pin ourselves down to a precise time, date, manner of action, but there will be consequences."
France is pressing the United Nations to refer the three-year-old civil war in Syria to the International Criminal Court for possible prosecution of war crimes and crimes against humanity.
Syria has promised to hand over or destroy its entire chemical weapons arsenal although it still possesses roughly 7.5 percent of declared chemicals and has not yet destroyed a dozen production and storage facilities.
The United States had agreed with its allies to "redouble efforts" to support Syria's moderate opposition and is willing to consider funneling aid directly to civilians in besieged areas using humanitarian agencies instead of the UN, Kerry said.
Humanitarian agencies, or non-governmental organizations, complain that despite multiple requests the United Nations has so far failed to share its methods in identifying those most in need and monitoring where its aid goes after delivery.
U.N. Secretary-General Ban Ki-moon has demanded that the Security Council act to ensure that Syria's warring parties adhere to UN demands for aid access. Kerry too expressed frustration over Syria's worsening humanitarian crisis.
"We are open to anything that will get the aid to the people, and we are very frustrated with the current process. It is not getting to people," Kerry said.
"We need to be able to get aid more directly and we're going to work to do that."
Australia, Luxembourg and Jordan say Syria's warring parties have ignored a UN resolution adopted in February that demands greater U.N. humanitarian access to Syrians and are drafting a second resolution that calls for further measures.
The Security Council could impose targeted sanctions on individuals violating international humanitarian law, although Russia is again unlikely to support such a move, diplomats say.
"We are open to the idea of providing aid through any means that will get to the people who need it," Kerry said.
Kerry declined to say whether ramping up support for the opposition meant providing vetted rebel groups with portable surface-to-air missiles to stop government air attacks.
"I'm not going to discuss what specific weapons," Kerry said. "But I will say that out of today's meeting every facet of what can be done is going to be ramped up."
Western and Gulf allies will meet in coming days to discuss ways of increasing support for the opposition, he said without elaborating.
Kerry said the United States and its European and Gulf allies rejected planned Syrian elections as illegitimate.
"Together we are unified in saying that Assad's staged elections are a farce - they are an insult (and) they are flawed," he said.
Additional reporting by William James; writing by Guy Faulconbridge; editing by Andrew Roche