U.N. chemical weapons inspectors on Monday visited one of the Damascus suburbs that was allegedly hit last week with poison gas in an attack that left hundreds of people dead and increased the likelihood of U.S. military intervention in the region’s bloodiest conflict.

The visit came as Washington’s Western allies indicated that they would back U.S. military action against Syria in response to the alleged attack, even without a U.N. mandate, intensifying speculation that some form of military intervention is imminent.

The convoy carrying the inspectors came under sniper fire in its first attempt to access the affected town of Moadamiya, and the lead vehicle was hit, U.N. officials said. But the team was able to regroup and complete the journey to the rebel-held suburb, one of three on the outskirts of Damascus that were targeted in Wednesday’s attack.

Video live-streamed from a field hospital showed members of the U.N. chemical weapons investigation team, dressed in blue helmets and bulletproof vests, examining patients and talking to doctors who had treated some of the victims.

“This is the effect of chemicals,” one man, who appeared to be a doctor, explained to one of the inspectors, who took notes on a clipboard.

Timeline: Major events in Syria’s tumultuous uprising that began in March 2011.

In New York, U.N. spokesman Farhan Haq said the inspectors had a “very productive” day, collected “some samples” and intended to continue their fieldwork Tuesday. Haq stressed that the inspectors do not have a mandate to assign responsibility for a chemical weapons attack, only to establish whether one has occurred.

Russia has repeatedly blocked action against Syria at the U.N. Security Council, leaving the Obama administration with few options palatable to a president who has repeatedly vowed to conduct foreign policy through international institutions.

But the powerful evidence that chemical weapons were used in rebel-held strongholds of Damascus last week — including multiple videos of children gasping, drooling and dying by the dozens — has abruptly shifted the discussion on whether military intervention is an option. Doctors Without Borders, the French relief agency, said three hospitals it supports in the afflicted areas had treated 3,600 patients who were displaying neurotoxic symptoms, of whom 355 died.

The Syrian government has accused the rebels of responsibility and says some of its troops also have been affected by an unspecified nerve gas.

But Secretary of State John F. Kerry pointed the finger squarely at President Bashar al-Assad’s forces on Monday, saying that the use of chemical weapons was “undeniable” and that the Syrian government’s decision to allow inspections was “too late to be credible.”

The Obama administration has already said it has evidence that the Assad regime has used chemical weapons on several occasions, but the scale of this attack, if confirmed, would unequivocally cross a “red line” set by the president a year ago.

On Monday the foreign ministers of Britain, France and Turkey said in separate interviews that they would be prepared to back U.S. action outside the parameters of a U.N. mandate.




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“Is it possible to respond to chemical weapons without complete unity on the U.N. Security Council?” British Foreign Secretary William Hague said on BBC Radio. “I would argue yes, it is; otherwise it might be impossible to respond to such outrages, such crimes, and I don’t think that’s an acceptable situation.”

Turkish Foreign Minister Ahmet Davutoglu told Turkey’s Milliyet daily newspaper that more than 35 nations are considering joining the United States in taking action against Syria and that Turkey is among them.

“We always prioritize acting together with the international community, with United Nations decisions. If such a decision doesn’t emerge from the U.N. Security Council, other alternatives . . . would come onto the agenda,” Davutoglu said.

French Foreign Minister Laurent Fabius predicted that there will soon be a response.

“It will be negotiated in the coming days,” Fabius told Europe 1 radio Monday. “All the options are open. The only option that I can’t imagine would be to do nothing.”

The sudden flurry of meetings and diplomacy appears to have unnerved a regime that has grown accustomed to steadily escalating its use of force without stirring much in the way of international action.

After initially balking, Syria agreed Sunday to allow the U.N. inspectors to visit the areas where the alleged attack occurred. The agreement coincided, however, with a sharp increase in shelling against the two eastern suburbs where most of the victims died.

The U.N. team headed for Moadamiya, west of the capital, in part because it was calmer than the eastern areas, U.N. officials said. But the vehicles nonetheless were “deliberately shot at multiple times by unidentified snipers” as they traversed the no-man’s land between rebel and government-held territory, a U.N. statement said.

The United Nations did not apportion blame for the attack, but the rebels and the government accused each other.

The official Syrian government news agency SANA said that “armed terrorist groups” opened fire as the inspectors approached. Rebel spokesman Zaidan al-Sabaa said it was loyalist troops and militiamen who shot at the team.

Meanwhile, top military chiefs from several countries gathered Monday in the Jordanian capital, Amman, for a meeting that was originally set to discuss ways to improve the security of Syria’s neighbors.

“The Syrian crisis has grown from a humanitarian tragedy into a regional crisis that threatens every neighboring state’s security, economy and stability,” said Mahmoud Irdaisat, a former Jordanian air force general and head of the Center for Strategic Studies at the country’s King Abdullah II Academy for Defense Studies. “Right now, local and international pressures are too great for the West and Arab states not to reach an agreement over military action.”

The meeting includes military chiefs from Britain, France, Germany, Italy, Canada, Turkey, Saudi Arabia, Qatar and Jordan, according to a Jordanian security official quoted by the Associated Press. Gen. Martin Dempsey, chairman of the U.S. Joint Chiefs of Staff, is also participating. He has expressed strong opposition to even limited intervention in Syria.

Ahmad Ramadan in Beirut, Colum Lynch in New York and Taylor Luck in Amman contributed to this report.