By Barbara Starr
American intelligence analysts are at odds over what the United States knows about the location of Syria's chemical weapons, CNN has learned.
Disagreement within the intelligence community surfaced over the past few weeks as spy agencies observed Syria - fearing a possible U.S. military strike - moving a significant amount of chemical weaponry, according to two U.S. officials familiar with internal discussions.
The lack of consensus raises concerns about accountability should the regime of Syrian President Bashar al-Assad proceed with its stated intention of turning over chemical stockpiles to international control and creates potential targeting problems should the United States opt for military action, CNN has learned.
At one end of the spectrum, some analysts believe the United States might not be able to verify the location of up to 50 percent of Syria's chemical weapons, the officials said. At the other end, some agencies conclude the United States knows where most of them are stored, both officials said.
The officials declined to be identified because of the sensitive nature of the information.
Both work in different parts of national security agencies, but outlined the same scenario of widely varying views of intelligence analysts.
Neither would specify precisely which agencies disagree. But until the latest crisis, several administration officials had told journalists - without full attribution - the United States knew the location of most stockpiles.
Separately on Friday, a third senior U.S. official said "our confidence in being able to track the chemical weapons is going down" because of recent movements.
He said the only solution is "we have to work on the intelligence."
CNN and other news organizations have reported over the past year that chemical stockpiles had regularly been moved by the regime for security purposes when rebel fighting grew close to storage areas, and that the United States was able to track them using satellites, intercepts and human based intelligence.
One official said the current disagreement about intelligence "shouldn't be a surprise."
He noted an agency like the National Security Agency "is going to listen to intercepts and see it through that lens; the (Defense Intelligence Agency) is going to look at military information and see it through that lens. The CIA likes to think it's looking at the problem holistically."
Intelligence analysis is open to interpretation and opposing views are not uncommon.
In one notable instance, the intelligence community had a range of certainty about whether a compound discovered in Pakistan was indeed Osama bin Laden's hideaway, because they were relying on interpretation of clues but had no photo or sighting of the al Qaeda leader.
Navy SEALs raided the building and killed bin Laden in May 2011.
It will be up to James Clapper, the director of national intelligence, to present President Barack Obama with an overall assessment.
Clapper's office did not immediately respond to CNN's request for comment.
Analysts often face the dilemma of verifying information through more than one source.
"The majority, if not all of it, is in area controlled by the Assad forces," Secretary of State John Kerry told the House Armed Services Committee on Tuesday. "We're going to have to be able to know that it can all be accounted for."
U.S. uncertainty about the location of the weapons began to emerge about two weeks ago.
"Most of the movement was when it looked like a military strike might be imminent," one of the officials said. "We saw significant movement at some sites."
He described this as being within the "12 to 20" major sites the United States watches closely.
Since that time, "everything is locked down," the official said. But he added, "we have less confidence we know where everything is and what might have been moved."
It's not entirely clear what the specific motivation was for moving the weapons at that time, the official said. One theory - the regime may have feared rebels could gain access to them.