(CNN) -- The United States believes Syria has moved "some" chemical weapons in recent days, a U.S. official told CNN on Friday.
The stockpile is believed to be is under the control of regime forces, the source said.
The official, who would only speak anonymously because the source was speaking about intelligence matters, said the reason behind the movement is unclear. The source could not say what types of chemical stockpiles were involved or how much was moved.
The United States has had satellite surveillance of Syria's key weapons sites since the unrest began.
But it's also likely some of the information came from communications intercepts based on conversations CNN has had with other sources knowledgeable about this matter.
Possible reasons for the move could range from whether it was to better protect the material from the fighting of the spreading revolt in Syria or more ominously to use against the population, the sources said.
The Wall Street Journal was first to report the suspicion.
The Pentagon has refused all comment. The State Department spokeswoman said Syria's government needs to ensure protection of its weapons stash.
"We have repeatedly made it clear that the Syrian government has a responsibility to safeguard its stockpiles of chemical weapons, and that the international community will hold accountable any Syrian officials who fail to meet that obligation," said Victoria Nuland, the State Department spokeswoman.