The US would only take action on Syria in concert with the international community and with legal justification in response to the alleged chemical weapons attacks in Damascus, U.S. Defense Secretary Chuck Hagel said on Monday.

Hagel, speaking on a trip to Indonesia, declined to discuss U.S. military options under consideration by the White House, or to say whether he thought a military response was likely.

"The United States is looking at all options regarding the situation in Syria. We're working with our allies and the international community," Hagel told a news conference in Jakarta.

"We are analyzing the intelligence. And we will get the facts. And if there is any action taken, it will be concert with the international community and within the framework of legal justification."

Hagel planned to speak with his British and French counterparts about the situation in Syria, a senior U.S. official said, speaking on condition of anonymity. The timing of those upcoming calls was unclear, the official said.

The official said there was growing confidence that the Syrian government had used chemical weapons against civilians in suburbs of Damascus last week and admonished the delays in allowing U.N. inspectors access to the sites.

"Our confidence is growing that this was, in fact, an episode involving the use of chemical weapons by the Syrian regime," the official said. - Reuters