In an interview with BBC television during a trip to Southeast Asia, Hagel said Obama had asked the Pentagon for "all options for all contingencies," and that American and allied forces are in position to mete out any ordered punitive measures against Syrian President Bashar Assad.
“I think the intelligence will conclude that it wasn't the rebels who used it, and there'll probably be pretty good intelligence to show that the Syria government was responsible — but we'll allow the time to come together to provide that information,” Hagel told the BBC during a visit to the sultanate of Brunei.
“We are prepared. We have moved assets in place to be able to fulfill and comply with whatever option the president wishes to take,” Hagel said.
In Washington, Pentagon Press Secretary George Little told reporters that Hagel had also called his counterparts in Britain and France to coordinate preparations for a response to the suspected chemical weapons attacks last week.
"Secretary Hagel conveyed that the United States is committed to working with the international community to respond to the outrageous chemical attacks that have claimed the lives of innocent civilians in Syria," Little said of the Pentagon chief's calls to British Defense Secretary Philip Hammond and French Defense Minister Jean-Yves Le Drian.
Shortly after Hagel's comments and consultations, French President Francois Hollande told a Paris gathering of his country's ambassadors that "France is ready to punish those who took the heinous decision to gas innocents.”
British Prime Minister David Cameron cut short his vacation and returned to London to be on hand for an early convening of Parliament on Thursday to discuss and likely vote on a "clear motion" in response to the reported use of chemical weapons.
"What we’ve seen in Syria are appalling scenes of death and suffering because of the use of chemical weapons by the Assad regime, and I don’t believe we can let that stand," Cameron said in a televised interview, adding that any response from the international community should be "legal" and "proportionate."
But the British leader stressed that any action would be aimed at deterring any future use of chemical weapons and was in no way a signal of intent for "getting involved in a Middle Eastern war."
There was also an indication from the Arab League on Tuesday that the political bloc uniting many of Syria's neighbors might back military action to punish Assad's regime.
In a bulletin from Cairo, the Arab League said it had determined that the Syrian government was to blame for the chemical-weapon attacks that killed hundreds.
The Arab League called on the United Nations to sanction Syria. But the U.N. Security Council, the only arm of the world body empowered to order punitive action, is unlikely to reach the necessary unanimous decision because Russia opposes any military intervention against its Syrian ally.
Russian Foreign Minister Sergei Lavrov on Monday denounced the momentum building for waging air strikes against Syria, saying those accusing Assad of being behind the attacks last week had no proof. On Tuesday, Foreign Ministry spokesman Alexander Lukashevich called on the international community to show "prudence" over the crisis and to abide by international law.
"Attempts to bypass the Security Council, once again to create artificial groundless excuses for a military intervention in the region, are fraught with new suffering in Syria and catastrophic consequences for other countries of the Middle East and North Africa," Lukashevich said in a statement.
International treaties and laws of war prohibit any use of weapons of mass destruction, including chemical, biological and nuclear armaments.
Analysts said the injuries sustained by survivors of the incidents last week were consistent with exposure to a caustic substance like sarin gas, and many of the deaths -- estimated by rebels to possibly exceed 1,000 -- were reported to have been due to asphyxiation.
Times Staff Writer Henry Chu in London contributed to this report.