The US, along with several key allies, is prepared to launch a military intervention in Syria should the Assad government resort to using its chemical weapons against the rebels, the London Times reported on Wednesday.

A military source told the Times that US forces could be ready “rapidly, within days,” if Syrian chemical weapons were activated, and implied that the necessary forces were already in the region.

“It won’t require major movement to make action happen. The muscle is already there to be flexed,” the source said. “It’s premature to say what could happen if a decision is made to intervene. That hasn’t taken shape, we’ve not reached that kind of decision. There are a lot of options, but it [military action] could be launched rapidly, within days.”

An American-led intervention could involve US European allies like the UK, the paper said.

Countries which border Syria such as Jordan, Turkey and even Israel could also be included in a US-led military coalition, Maariv reported on Wednesday morning.

However, King Abdullah II said that Jordan “will not be party to any military intervention in Syria, which is contrary to our position, principles and national interests.”

Speaking with state-sponsored newspaper al-Rai on Wednesday, the King added that Jordan would “defend our homeland” if the kingdom faced danger.

The fate of Syria’s chemical weapon stockpiles, believed to be the third-largest in the world, is emerging as a key international issue as the civil war continues to generate chaos.

Israel is particularly concerned that Syrian chemical and biological weapons could fall into the hands of terrorists and be used against Israel.

“Together with the international community, we are closely monitoring developments in Syria regarding its stores of chemical weapons… Such weapons must not be used and must not reach terrorist elements,” Prime Minister Benjamin Netanyahu said Tuesday at a forum in Jerusalem.

On Monday US President Barack Obama warned Syria that “the world is watching” and that “the use of chemical weapons is and would be totally unacceptable.” He said it would be a “tragic mistake” if Bashar Assad’s government were to use them, and warned him that if he does so, “there will be consequences and you will be held accountable.”

On Tuesday, NATO foreign ministers green-lighted a plan to install Patriot air defense batteries along the southern Turkish border as a defense measure against possible missile or chemical attacks from Syria. The defensive missile system is expected to be in place within the next several weeks.

Turkey, which has seen several fatal instances of spillover fighting along its 911-kilometer border with Syria, has been a NATO member since the 1950s. NATO Secretary General Anders Fogh Rasmussen said on Tuesday that “we stand with Turkey” and warned against any attacks on the NATO member.

He said he would expect “an immediate reaction from the international community” if chemical weapons were to be used by Syria, a possibility he called “completely unacceptable.”

Ilan Ben Zion contributed to this report.