The media countdown to possible Western military action in Syria gathered momentum Tuesday as U.S. Defense Secretary Chuck Hagel told the BBC that the U.S. military is "ready to go" if President Barack Obama orders action in response to alleged chemical weapons attacks, and British Prime Minister David Cameron called an emergency session of parliament to debate the issue.
"We have moved assets in place to be able to fulfill and comply with whatever option the president wishes to take," Hagel said in the interview. Cameron's spokesman said earlier that Britain and its allies believed that the alleged chemical attacks in Syria requires international action and that Western powers are considering a "proportionate response."
Cameron later clarified that the U.K. has not made a decision on whether to take action in Syria, adding that any military action must be "specific" and that Britain does not want to involve itself in the country's civil war. U.S. officials quoted by the Washington Post expressed a similar preference for a limited "punishment" action to deter the Syrian regime from using chemical weapons and for avoiding entanglement in the country's power struggle.
The warnings of imminent action come in response to allegations last week that hundreds of civilians were killed in poison gas attacks. Syria's civil war has killed more than 100,000 people since March 2011, but Secretary of State John Kerry on Monday described the alleged attacks as a "moral obscenity" that demanded accountability.
However, a spokesperson for the U.N. said follow-up investigations planned for Tuesday were being postponed until Wednesday to ensure security.
"Following yesterday's attack on the U.N. convoy, a comprehensive assessment determined that the visit should be postponed by one day in order to improve preparedness and safety for the team," the spokesperson said in a statement.
With U.N. authorization for military action unlikely in the near term, the U.S. would be forced to seek international legitimacy for Syria strikes in alternative multilateral bodies such as NATO and the Arab League.
But with the Arab League's rejection of a retaliatory strike President Obama may be left without the broad regional support he is seeking.
Gen. Wesley Clark, who was NATO supreme commander during the Kosovo war, had signaled that backing from groups such as the Arab League would be a crucial step before the U.S. decides to take action. "You have to start by building a coalition of the willing around a regional organization," Clark said.
Prior to the Arab League's declaration, Anja Manuel, a Stanford University international-relations professor and former State Department official, had said Washington would likely be able to count on support from a number of Arab states, including Qatar and Saudi Arabia because "they have been supporting the rebels in Syria for several years now -- not always the rebel groups that America would support, but they might be brought around to cooperating with us."
But Jeffrey Laurenti, a senior fellow at the Century Foundation, a public-policy research organization, said that the U.S. mission is unlikely to go so far as picking particular sides or toppling Assad. Rather, Obama wants to enforce the chemical weapons "red line" he first mentioned in 2012.
"You essentially have two different approaches to an American military action in Syria," Laurenti said.
"One is a military intervention that is designed to change the military dynamic on the ground by deeply degrading the government's military capabilities, a wide-ranging air attack on Assad's forces, so whichever of the disparate rebel groups might be able to take advantage of the government's loss of capability and help bring down the regime. The other is purposefully limited to enforce President Obama's red line that aims at deterring the Syrian government from using them again as the civil war continues, to put money where Obama's mouth was. My sense is the second."
The most widely shared prediction among analysts on the form taken by any possible U.S. military action is a barrage of sea-launched cruise missiles targeting Syrian military installations and artillery batteries deemed complicit in the alleged chemical weapons attack.
Wilson Dizard contributed to this report. With Al Jazeera and wire services.