FRANCE is seeking a reaction with "force" if a massacre in Syria involving chemical weapons is confirmed, French Foreign Minister Laurent Fabius said.

"If it is proven, France's position is that there must be a reaction," Fabius told BFM-TV, speaking of a "reaction with force" while judging it "impossible" to send ground troops.

The French Foreign Minister's remarks come after horrific images emerged of victims of a military offensive in the rebel-held eastern Damascus suburbs where the opposition says a chemical weapons attack killed over 100 people.

The images showed lifeless children - wrapped in simple white cloths, their pale faces unmarked by any wound - lined up shoulder to shoulder in a vivid demonstration of an attack Wednesday in which activists say the Syrian regime killed at least 1300 people with toxic gas.

The Syrian government adamantly denied using chemical weapons in an artillery barrage targeting suburbs east of Damascus, calling the allegations "absolutely baseless.''

The opposition National Coalition's George Sabra said more than 1300 people had been killed in what he described as a "coup de grace that kills all hopes for a political solution in Syria''.

"The Syrian regime is mocking the UN and the great powers when it strikes targets near Damascus, while the (UN weapons inspectors) are just a few steps away,'' he said.

Prime Minister Kevin Rudd says news of the massacre in Syria is "repugnant" and he wants United Nations weapons inspectors to investigate.



"The use of weapons of mass destruction in any circumstances is intolerable and unacceptable in any civilised nation," Mr Rudd told reporters in Victoria on Thursday.



"When weapons of mass destruction, including chemical weapons, are used against civilian targets it is repugnant."

The United States sees "strong indications" that Syria's government used chemical weapons in the attacks - in what would be a significant escalation of poison-gas use in the civil war, the Wall Street Journal reports.

"There are strong indications there was a chemical weapons attack— clearly by the government," a senior administration official said. "But we do need to do our due diligence and get all the facts and determine what steps need to be taken."

Following an emergency meeting of the UN Security Council in New York, the council's president, Argentina's envoy Maria Cristina Perceval, said: "There must be clarity on what happened and the situation must be followed carefully.''

She added that members "welcomed the determination of the secretary general to ensure a thorough, impartial and prompt investigation''.

The 15-nation body expressed "strong concern'' about the allegations and agreed that any chemical weapons use is "a violation of international law''.

The US, Britain and France have demanded that a team of UN experts already in the country be granted immediate access to investigate the claims.

Videos and photographs showed row upon row of bodies wrapped in white shrouds lying on a tile floor, including many children. There was little evidence of blood or conventional injuries and most appeared to have suffocated.

A pharmacist who treated victims said: "Their mouths were foaming, their pupils were constricted, and those who were brought in while still alive could not draw their breaths and died subsequently."

Survivors, some twitching uncontrollably, lay on gurneys with oxygen masks covering their faces.

UN Secretary General Ban Ki-moon's office said he was "shocked'' by the reports and that UN weapons experts in Syria to probe previous allegations were in discussions with Damascus.

Security Council members France, Britain, the United States, Luxembourg and South Korea requested the meeting, which was held behind closed doors.

Britain, France, Germany and the United States also sent a formal request for an investigation of the incident to Ban's office, citing ''credible reports of the use of chemical weapons'' in a letter.

Western governments demanded immediate access for the inspectors to investigate the new allegations. Russia, a longstanding ally of the Damascus regime, echoed the call for an inquiry but said it suspected a ''provocation'' by the opposition and its foreign backers.

The White House said it's "deeply concerned" about reports that chemical weapons were used by Syria's government against civilians.

The allegations of gassing civilians dwarfed all previous such accounts in the increasingly bloody civil war.

The Syrian Network for Human Rights reported that 647 Syrians were killed in the attacks, and it attributed nearly 590 of those deaths to chemical weapons.

The Syrian Observatory for Human Rights, considered the most authoritative group tracking casualties in the conflict, estimated at least 136 dead from an air assault but didn't address whether chemical weapons appeared to be involved.

Videos distributed by activists, the authenticity of which could not immediately be verified, showed medics attending to suffocating children and hospitals being overwhelmed.

More footage showed dozens of people laid out on the ground, among them many children, many covered in white sheets.

One video posted on YouTube showed what it said was a case of hysteria following a chemical strike in the eastern suburbs.

A young girl held her head in her hands and frantically repeated "I'm alive'', as a man in a white coat tried to comfort her.

Observatory director Rami Abdul-Rahman cited activists in the area who said "poisonous gas'' was fired in rockets as well as from the air. He said that he had documented at least 136 deaths, but said it was not clear whether the victims died from shelling or toxic gas.

The Local Coordination Committees activist group said hundreds of people were killed or wounded. The Syrian National Coalition, the main Western-backed opposition group in exile, put the number at 1300, basing its claim on accounts and photographs by activists on the ground.

Syria is said to have one of the world's largest stockpiles of chemical weapons, including mustard gas and the nerve agent sarin.

Jean Pascal Zanders, an independent researcher who specialises in chemical and biological weapons and disarmament, said that in videos of the aftermath of the attacks, the hue of the victims' faces appeared to show many suffered from asphyxiation.

However, he said the symptoms they exhibited were not consistent with mustard gas or the nerve agents VX or sarin.

Mustard gas would cause blistering of the skin and discoloration, while the nerve agents would produce severe convulsions in the victims and also affect the paramedics treating them - neither of which was evident from the videos or reports.

"I'm deliberately not using the term chemical weapons here,'' he said. "There's plenty of other nasty stuff that was used in the past as a chemical warfare agent, so many industrial toxicants could be used too.''

A pharmacist in the town of Arbeen who identified himself as Abu Ahmad said he attended to dozens of wounded people in a field hospital after the shelling on Zamalka and Ein Tarma early Wednesday. He said many were moved to Arbeen.

The bodies of 63 of the dead had signs of a chemical weapons attack, he said, though he could not confirm this.

"Their mouths were foaming, their pupils were constricted, and those who were brought in while still alive could not draw their breaths and died subsequently,'' he told The Associated Press via Skype.

"The skin around their eyes and noses was grayish.''

Activists in nearby Zamalka told Abu Ahmed that an additional 200 people died in that town on Wednesday.

Syria's information minister, Omran al-Zoubi, denied government troops used chemical agents, calling the activists' claim a "disillusioned and fabricated one whose objective is to deviate and mislead'' the U.N. mission.

The head of the U.N. team, which has a mandate to investigate previous claims of alleged chemical attacks, said he wants to look into the latest claims.

Speaking to Swedish broadcaster SVT, Ake Sellstrom said the high numbers of dead and wounded being reported "sound suspicious.''

"It looks like something we need to look into,'' Sellstrom, who is Swedish, was quoted as saying.

He said a formal request from a member state would have to go through U.N. channels and Syria would need to agree - and there is no guarantee that it would.

Ghazwan Bwidany, a doctor treating the injured, told the BBC the main symptom, especially among children, was suffocation, as well as salivating and blurred vision.

"We don't have the capability to treat all this number of people," he said.

Opposition sources accused the army of multiple chemical weapons strikes -- one in Moadamiyet al-Sham, southwest of Damascus, and more in the capital's eastern suburbs.

The Local Coordination Committees (LCC), a network of activists, reported hundreds of casualties in the "brutal use of toxic gas by the criminal regime''.

And in videos posted on YouTube, the Syrian Revolution General Commission, another activist group, showed what it called "a terrible massacre committed by regime forces with toxic gas.''

In one video, children are seen being given first aid in a field hospital, notably oxygen to help them breathe. Doctors appear to be trying to resuscitate unconscious children.

Other images - distributed by the opposition Shaam News Network - show lines of uncovered bodies, many of them children.

Specialists in the impact of chemical weapons said the video evidence was not entirely convincing.

"At the moment, I am not totally convinced because the people that are helping them are without any protective clothing and without any respirators,'' said Paula Vanninen, director of Verifin, the Finnish Institute for Verification of the Chemical Weapons Convention.

"In a real case, they would also be contaminated and would also be having symptoms.''

John Hart, head of the Chemical and Biological Security Project at Stockholm International Peace Research Institute said he had not seen the telltale evidence in the eyes of the victims that would be compelling evidence of chemical weapons use.

"Of the videos that I've seen for the last few hours, none of them show pinpoint pupils... this would indicate exposure to organophosphorus nerve agents,'' he said.

State news agency SANA said "reports on the use of chemical weapons in Ghouta (the Damascus suburbs) are totally false. It's an attempt to prevent the UN commission of inquiry from carrying out its mission.''

The UN Security Council met to discuss the allegations as UN officials said that talks were already under way with President Bashar al-Assad's government on securing access to the alleged attack sites.

The head of the UN inspection mission, Aake Sellstroem, was ``in discussions with the Syrian government on all issues pertaining to the alleged use of chemical weapons, including this most recent reported incident,'' a statement said.

Washington demanded that the inspectors be given unfettered access.

"For the UN's efforts to be credible, they must have immediate access to witnesses and affected individuals, and have the ability to examine and collect physical evidence without any interference or manipulation from the Syrian government,'' said White House spokesman Josh Earnest.

Washington has previously described chemical weapons use as a red line that might prompt it to intervene militarily in Syria.

British Foreign Secretary William Hague said: "I hope this will wake up some who have supported the Assad regime, to realise its murderous and barbaric nature.''

Moscow, which has said it has proof of chemical weapons use by the rebels in March, expressed scepticism about the opposition's claims.

The foreign ministry said the timing of the allegations as UN inspectors began their work "`makes us think that we are once again dealing with a premeditated provocation.''

The heavy bombing on the outskirts of the capital could be heard by residents of Damascus, where a grey cloud capped the sky.

The Britain-based Observatory, which relies on a vast network of activists on the ground and medics, said the army operation was aimed at the recapture of Madhamiyat el-Sham, an area southwest of Damascus.

The Syrian Observatory called for inspectors to hastily visit the stricken sites and ensure access for medical aid.

UN chief Ban Ki-moon insisted Monday that the inspectors be granted unrestricted access to Syrian sites where chemical weapons have allegedly been used in the country's 29-month-old conflict.

The inspectors, expected to visit three sites including Khan al-Assal near Aleppo in the north, are due to be in Syria for 14 days, with the possibility for an extension of the mission.