(This post last updated at 4:20 p.m. ET)
President Obama has been meeting with his national security team to discuss reports of the Syrian government's use of chemical weapons, a White House official said Saturday, amid strong hints that a U.S. military strike was on the table.
Those discussions were taking place as the humanitarian group Doctors Without Borders said reports it received from hospitals in Damascus after the attack indicated that 355 people had died from symptoms consistent with being exposed to a neurotoxic agent.
"We have a range of options available, and we are going to act very deliberately so that we're making decisions consistent with our national interest as well as our assessment of what can advance our objectives in Syria," the White House official, speaking on background, said.
The statement follows comments Friday by Defense Secretary Chuck Hagel that the president has asked the Pentagon for options on Syria and that U.S. warships armed with cruise missiles were being repositioned in the Mediterranean.
Hagel said the Defense Department "has a responsibility to provide the president with options for contingencies, and that requires positioning our forces, positioning our assets, to be able to carry out different options whatever options the president might choose."
Obama, who has shown reluctance to intervene in Syria's 2-1/2-year civil war has said that the use of chemical weapons would be a "red line" for the United States.
In June, the White House said it had "high confidence" of an attack involving deadly sarin gas that killed 100 to 150 Syrians.
Angela Kane, the United Nations disarmament chief, arrived in Damascus on Saturday in hopes of persuading the government to allow a team to examine the site of Wednesday's reported attack in Ghouta district, a suburb of the capital.
Obama, in an interview with CNN aired on Friday, said the attack was "clearly a big event of grave concern", but he cautioned that U.N. investigators should be given time to determine whether chemical weapons were used.
"If the U.S. goes in and attacks another country without a U.N. mandate and without clear evidence that can be presented, then there are questions in terms of whether international law supports it, do we have the coalition to make it work?" the president said in his first public comments since the alleged attack.
Syrian state television has suggested rebels are to blame for the attack this week. It said government soldiers "suffocated" as they tried to enter Jobar, one of the towns in the Ghouta district where chemical weapons are said to have been used.
That suggestion was echoed by Syria's deputy prime minister, Qadri Jamil, who blamed the rebels.
Jamil told The Associated Press on Friday that he was personally in favor of the U.N. looking into the Ghouta incident.
"We don't want to be like Iraq, opening our territory up to all sorts of investigators, going through our homes and bedrooms. Syria is a sovereign nation and will preserve its sovereignty," he told the AP in an interview at the prime minister's offices in the Damascus district of Kfar Sousseh.
Doctors Without Borders Mdecins Sans Frontires (MSF) said Saturday that in the three hours following the alleged attack on Wednesday, three hospitals in Damascus that it supports reported approximately 3,600 patients displaying symptoms consistent with exposure to a neurotoxic agent. Of those, 355 reportedly died, the humanitarian group said.
"Medical staff working in these facilities provided detailed information to MSF doctors regarding large numbers of patients arriving with symptoms including convulsions, excess saliva, pinpoint pupils, blurred vision and respiratory distress," said Dr. Bart Janssens, MSF director of operations, said in a statement.
"MSF can neither scientifically confirm the cause of these symptoms nor establish who is responsible for the attack," Dr. Janssens said. "However, the reported symptoms of the patients, in addition to the epidemiological pattern of the eventscharacterized by the massive influx of patients in a short period of time, the origin of the patients, and the contamination of medical and first aid workersstrongly indicate mass exposure to a neurotoxic agent."