The Pentagon is moving naval forces closer to Syria in a potential attempt to be prepared should President Obama order military strikes, Defense Secretary Chuck Hagel is suggesting.
The president asked the Department of Defense to put some matters in place regarding Syria, and that would include "positioning our forces," the Associated Press quotes Hagel as saying.
"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 ale to carry out different options - whatever options the president might choose," Hagel said.
Earlier Friday, Syria was coming under intense pressure to allow United Nations weapons inspectors access to the site of an alleged chemical attack as President Obama referred to the claims in Syria as a "big event of grave concern."
The president made the comments in a taped interview with CNN.
The conflict in Syria "is something that is going to require America's attention and hopefully the entire international community's attention," Obama said. He also warned against "jumping into stuff, that does not turn out well."
Obama said the United States needs to "think through" its response.
OBAMA: U.S. must 'think through' its response to Syria
Despite seemingly overwhelming evidence, the Syrian government continues to deny that it used chemical weapons. Three dozen countries, including the U.S., have now called for a U.N. investigation.
The British government appeared to indicate Friday that it believed the attack was of a chemical nature. "I know that some people in the world would like to say that this is some kind of conspiracy brought about by the opposition in Syria," Reuters reported British Foreign Secretary William Hague as saying. "I think the chances of that are vanishingly small and so we do believe that this is a chemical attack by the Assad regime."
On Friday, Russia, too, urged the Syrian government to give immediate access to the area near Damascus where the reported attack took place. Reuters reported that some Syrian activists are smuggling body tissue samples from the reported victims of the attacks to U.N. investigators.
The news comes following reports that some first responders to the claimed chemical attack in Syria have died after treating victims, providing more evidence that a weapon of mass destruction was used, opposition forces said.
"Some of them came down with similar symptoms and passed away," said Khaled Saleh on Thursday. Saleh is a spokesman for the Supreme Military Council of the Free Syrian Army, which the United States has provided with non-lethal aid. He said at least six doctors died after treating victims. "We don't have the (total) number of dead first responders yet," he said.
Saleh said he learned Thursday that one of the people he had been in touch with Wednesday who was treating people injured in the attack later passed away.
Between 800 and 1,700 people died Wednesday after a rocket attack on the Damascus suburb of Eastern Ghouta, according to the Syrian opposition, which reported receiving victims in area hospitals and finding more bodies in house-to-house searches Thursday.
Dan Layman, a spokesman for the Syrian Support Group, which supports the Free Syrian Army in Washington, said doctors, nurses and first responders reported Wednesday they'd experienced secondary symptoms while working with victims.
"The doctor I was talking to yesterday said the residue on the victims and their clothing was making the doctors get dizzy and have trouble breathing and (they) had to pour water on their faces and had to step out of the room," Layman said.
Layman said he learned Thursday two of those nurses died.
The reports come as the State Department says the U.S. government is still trying to find out what happened.
"There's a great sense of urgency in the administration to gather information on the ground," State Department spokeswoman Jen Psaki said. "If these reports are true, it would be a flagrant use of chemical weapons by the regime. The president will consider his options and discuss it with his national security team."
President Obama said a year ago, on Aug. 20, 2012, that use of chemical weapons by Syrian President Bashar Assad would cross a "red line" that would prompt the United States to take action that would have "game-changing" impact on the conflict.
The administration determined in June that Syrian pro-government forces had used chemical weapons and that Obama's red line had been crossed. The White House announced it would begin providing lethal aid to the Syrian armed opposition.
Saleh said that aid has yet to arrive.
A United Nations inspection team was in Damascus on Thursday to investigate three sites of earlier alleged chemical attacks, and Secretary of State John Kerry wants that team to have access to the site of Wednesday's alleged attack, Psaki said.
The United States and the U.N. team believe the armed opposition in Syria does not have chemical weapons capability, Psaki said.
"Given the U.N. team is on the ground right now, we're working to put pressure on the Syrian regime to allow access," she said.
One chemical weapons expert looking at the evidence says video from the scene of the attack is inconsistent with known chemical weapons injuries.
YouTube videos posted by Syrian activists of children gasping for air while being rinsed with water by barehanded medical personnel are not consistent with chemical weapons known to be in the Syrian arsenal, said Dan Kaszeta, managing director of U.K.-based security consultancy Strongpoint Security. Kaszeta worked 20 years on chemical biological and nuclear defense in the U.S. government and military.
Kaszeta said the videos show convulsions that affect some limbs but not all; no skin burns or blisters, which would indicate mustard gas; and no vomiting. He did not have access to any of the victims and his opinions are based solely on the video.
"(With) sarin or nerve agents there would be much more widespread symptoms," he said. "We need physical evidence, blood, urine, tissue, a chest X-ray of one of these guys who died."
Another chemical weapons expert, Hamish de Bretton-Gordon, the former commander of the chemical, biological and nuclear counterterrorism unit at the United Kingdom's Ministry of Defense, says a low-dose chemical weapons attack may explain the absence of some symptoms.
In March 1995, when the Japanese terrorist cult Aum Shinrikyo launched a sarin attack injuring about 6,000 people, first responders who were not present for the attack but treated victims later also experienced symptoms, Bretton-Gordon said.
Saleh said activists in the vicinity of Wednesday's attack have collected samples of victims' hair and blood, of soil and of pieces of munitions that landed in the area, but getting them to someone who can analyze them is another matter.
"The challenge is getting them out," Saleh said. "That area is completely surrounded by Assad's forces. You can't even get wheat in there to make bread."
The number of registered child refugees fleeing Syria's violence has topped the 1 million mark in another grim milestone of the deepening conflict, two U.N. agencies said Friday.
Roughly half of all the nearly 2 million registered refugees from Syria are children, and some 740,000 of those are under the age of 11, according to the U.N. refugee and children's agencies.
SYRIA: U.N. says Syrian child refugees tops 1 million mark
Kim Hjelmgaard contributed to this report from London; Dorell reported from McLean, Va. Follow @OrenDorell and @khjelmgaard on Twitter