The US is weighing up its military options in Syria in the aftermath of a deadly chemical weapons strike, with American naval forces moving closer to the country, Defense Secretary Chuck Hagel has hinted.
Although Hagel would not describe the specific movement of ships, he said the Pentagon was preparing for various options which are on the table for President Barack Obama.
"The president has asked the Defence Department for options," Hagel told reporters on a military plane, over the Pacific.
"The Defence 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."
The Associated Press reported that various options include launching Tomahawk cruise missiles, as they did against Libya in 2011.
The United Nations' top disarmament official, Angela Kane is expected to arrive in Syria on Saturday.
She is demand safe access to the site of Wednesday's alleged chemical weapons attack on civilians on the outskirts of Damascus, which Russia, a close ally of the regime, has called on Assad to grant.
Hagel said a determination on the chemical attack should be made swiftly because "there may be another attack coming," although he added that "we don't know" whether that will happen.
"The international community should and will act in concert on these kinds of issues," Hagel said.
The official stressed the Navy had received no orders to prepare for any military operations in connection with Syria.
The US has so far avoided specifically saying it believes that the deaths of at least 100 people - which eventually could be as many as ten times that number - was the result of a chemical attack by President Bashar Assad's forces. The UK's Foreign Secretary William Hague has been more specific, calling a gas attack "the only plausible explanation".
But President Obama has shied away from the same language, with no mention of his "red line", which he alluded to on the use of chemical weapons a year ago.
The Syrian government denies it was responsible for the attack, saying that rebel groups linked to Islamist extremists were behind the killing.