U.S. Weighing Options Against Syria

The word on Syria is that American firepower is nearby, and ready to act if it is called upon.

A senior administration official tells CNN the U.S. is working with its European allies to build a consensus on what to do next about Syria.

Within days, President Obama's national security team will present him with its final, detailed options in response to allegations that the Assad regime used chemical weapons on its own people, which Secretary of State John Kerry called  "a moral obscenity."

The White House is already making the case for taking action against Syria.

According to Secretary Kerry, "President Obama believes there must be accountability for those who would use the world's most heinous weapons against the world’s most vulnerable people."

Hence, “if the President gives the order, a senior defense official says four Navy destroyers in the Mediterranean Sea could execute a mission within hours. U.S. and British submarines are also likely nearby, all armed with cruise missiles,” reports CNN’s Chris Lawrence.

“The options are not designed to overthrow Assad's government, but send a message and deter any further use of chemical weapons, President Obama's ‘red line.’”

President Obama is now under pressure to keep his word and support his ultimatum. "Any time you throw down the diplomatic gauntlet, your words have repercussions,” Council on Foreign Relations president Richard Haas says.

While the U.S. is consulting with allies for a plan of action, as Lawrence reports, officials say it may not need a formal coalition to execute the response.

Follow along at CNN.com for developments.