Washington (CNN) -- With a flurry of diplomatic signals and activity, U.S. officials sought Tuesday to lay the groundwork for a possible military attack on Syria in response to last week's suspected chemical weapons attack that Washington blames on President Bashar al-Assad's regime.
Secretary of Defense Chuck Hagel and Secretary of State John Kerry both consulted allies and indicated potential imminent action by a coalition likely to include key NATO partners and regional powers.
Days after the United States moved warships armed with cruise missiles into the region, Hagel told the BBC on Tuesday that forces were ready to carry out a strike if ordered. A senior Defense Department official told CNN that any strike could be completed "within several days."
"We are ready to go, like that," Hagel told the BBC reporter.
"The options are there, the United States department of Defense is ready to carry out those options," the U.S. defense secretary said.
The White House insists President Barack Obama has yet to make a final decision on how to respond to what U.S. officials characterize as the worst chemical weapons attack since former Iraqi strongman Saddam Hussein launched a poison gas attack that killed thousands of Kurds in 1988.
On Monday, White House spokesman Jay Carney said the first step toward a military response in Syria would be the public release of a U.S. intelligence report on the August 21 event near Damascus that reportedly killed and wounded thousands.
That was planned to happen on Tuesday, according to a U.S. official who was not authorized to speak on the record.
Citing Kerry's strong statement Monday that essentially blamed the Syrian government for what the secretary called an "undeniable" chemical weapons attack and the expected release of the intelligence report, the official said the administration was "laying out the case for any action if and when President Obama decides."
Another official said the intelligence report would include forensic evidence and intercepted communications among Syrian military commanders.
On Monday, a senior administration official said Obama will be presented with final options regarding actions against Syria in the next few days. Assuming the president decides to go ahead with a military response, any action could come as early as mid-week, though it could be later, the official cautioned.
Factors weighing into the timing of any action include a desire to get it done before the president leaves for Russia next week for a summit with G8 allies, and before the administration has to make a decision on whether to suspend aid to Egypt because of the ongoing political turmoil there, the official explained.
The administration also wants it to be a quick response to the use of chemical weapons, rather than an intervention in Syria's ongoing civil war, the senior administration official said.
American officials are consulting with allies to ensure they are supportive of any U.S. action, which the senior administration official said would be very limited in scope and a direct reaction to the use of chemical weapons. Representatives of three allied governments involved in those top-level consultations said the goal is to reach a consensus as soon as possible.
"No one is talking about a long process," one European diplomat told CNN.
Marie Harf, a State Department spokeswoman, said any U.S. response would be "a determination on how to respond to a blatant use of chemical weapons, and it's not necessarily to change the entire situation on the ground in Syria."
However, Michael Doran, an analyst at the Brookings Institution's Saban Center for Middle East Policy, said a U.S. strike "can't just be one and done," but should be part of a plan to remove al-Assad.
"The president has been very reluctant to get involved. Public opinion has been against it. There's not a lot of support on the Hill," Doran told CNN on Monday. "And yet, here we are again. Time and time again, we get dragged further and further in."
The result could be "a Vietnam-type problem, where we kind of back our way into this, if we don't come up with a plan about how to win," he added.
Kerry spoke with his British, Jordanian, Qatari and Saudi counterparts Monday and with the secretary-general of the Arab League, Harf said.
"Obviously, the intelligence assessment is ongoing," she said. "But he reiterated that the president is studying the facts and will be making an informed decision about how to respond going forward."
Also Monday, a White House official ruled out sending ground troops to Syria or implementing a no-fly zone to blunt al-Assad's aerial superiority over rebels fighting to oust his regime.
For almost two years, Obama has avoided direct military involvement in Syria's civil war, only escalating aid to rebel fighters in June after suspected smaller-scale chemical weapons attacks by Syrian government forces.
However, last week's attack obliterated the "red line" Obama set just over a year ago against the use of Syria's chemical weapons stocks.
Carney told reporters Monday that Obama was evaluating "a response to the clear use on a mass scale with repugnant results of chemical weapons," adding that "there is very little doubt that the Syrian regime ... used those weapons."
Meanwhile,Kerry said that evidence "strongly indicates" chemical weapons were used in Syria and that "we know the Syrian regime maintains custody" of such weapons and has the rockets to use them.
Obama "will be making an informed decision about how to respond to this indiscriminate use" of chemical weapons, Kerry added, saying the president "believes there must be accountability" for those who use them.
Options available to Obama range from ordering limited missile strikes to continued diplomatic efforts labeled by critics as a "do-nothing" approach.
Opinion: How Al-Assad used chemical weapons to poison debate on Syria
Hagel said while visiting Indonesia on Monday that any U.S. action "will be in concert with the international community and within the framework of legal justification."
While U.N. Secretary-General Ban Ki-moon said Monday that the use of chemical weapons was a crime against humanity and must be punished, certain opposition by Syrian ally Russia and possibly China undermined the possibility that the Security Council would support a military mission.
Instead, a limited coalition of NATO partners such as Germany, France and Britain -- all of which have called for action against Syria -- and some Arab League members appeared more likely to provide the political backing needed by Obama to order U.S. missile strikes.
A senior administration official told CNN on Monday that the goals of any coalition military action would be to show al-Assad that there was a cost for using chemical weapons while preventing him from doing so again.
In addition, a military strike would seek to degrade the Syrian regime's capabilities enough to weaken it without causing it to fall to an opposition considered unprepared to assume power, the official said.
Possible coalition partners include NATO allies Britain, France, Germany and Canada, as well as regional powers Qatar, Turkey, Saudi Arabia and the United Arab Emirates.
Last month, Joint Chiefs Chairman Gen. Martin Dempsey provided Congress with a list of declassified U.S. military options for Syria that emphasized the high costs and risks of what he said would amount to "an act of war" at a time of deep budget cuts.
U.S. official: Almost no doubt al-Assad regime used chemical weapons
Dempsey's letter, dated July 19, listed U.S. assets in the region including Patriot missile defense batteries in Turkey and Jordan, as well as F-16 jet fighters positioned to defend Jordan from possible cross-border trouble. In addition, the Pentagon has sent four warships armed with cruise missiles to the region.
According to U.S. officials, updated options offered the president in recent days included:
• Cruise missiles fired from one of four Navy destroyers deployed in the Mediterranean Sea. The missiles would be used to strike "command and control" facilities such as command bunkers, or the Syrian regime's means of delivering chemical weapons: artillery batteries and launchers. There is no indication that the missiles would strike actual chemical weapons stockpiles.
• Military jets firings weapons from outside Syrian airspace. This option carries additional risks and is considered less likely.
"They have to be careful to do this in concert with our allies," Democratic Rep. Adam Schiff of California, a member of the House Intelligence Committee, told CNN on Sunday, adding that "I don't think the White House is going to want to risk American lives by sending pilots over Syria, so that really limits our options to cruise strikes and think that's probably where the White House is going to go."
Cruise missile strikes could be "very punishing" on al-Assad's missile supplies and aircraft without going after the chemical weapons stockpiles to risk dispersing them, Schiff said.
To Aaron David Miller, a vice president at the Woodrow Wilson International Center, the situation is forcing Obama to shift from being an "avoider-in-chief" regarding military involvement in Syria.
"It's almost inevitable that the president will authorize some form of military action," Miller told National Public Radio in an interview broadcast Monday.
He said he expected a significant response that amounts to "a warning that lays down this time a red line that the president intends to enforce, not one that turns pink."
"It cannot simply be a couple of cruise missiles into a storage shed somewhere," Miller said, adding that the goal was to deter al-Assad rather than topple him or radically shift the balance in Syria at this time. "The president's not on the verge of becoming the cavalry to rescue the country."
Schiff agreed that Obama has little choice but to respond strongly.
"In terms of the credibility of the White House," he said, "the cost of not acting now, I think, exceeds the cost of acting."
Chris Lawrence. Jill Dougherty and Tom Cohen, CNN