Syria Moves Its Chemical Weapons and Gets Another Warning WASHINGTON - The Syrian military's movement of chemical weapons in recent days has prompted the United States and several allies to repeat their warning to President Bashar al-Assad that he would be "held accountable" if his forces used the weapons against the rebels fighting his government. The warnings, which one European official said were "deliberately vague to keep Assad guessing," were conveyed through Russia and other intermediaries. What exactly the Syrian forces intend to do with the weapons remains murky, according to officials who have seen the intelligence from Syria. One American official provided the most specific description yet of what has been detected, saying that "the activity we are seeing suggests some potential chemical weapon preparation," which goes beyond the mere movement of stockpiles among Syria's several dozen known sites. But the official declined to offer more specifics of what those preparations entailed. Over the weekend, the activity in Syria prompted a series of emergency communications among the Western allies, who have long been developing contingency plans in case they decided to intervene in an effort to neutralize the chemical weapons, a task that the Pentagon estimates would require upward of 75,000 troops. But there were no signs that preparations for any such effort were about to begin. So far, President Obama has been very cautious about intervening in Syria, declining to arm the opposition groups directly, or even to formally recognize a newly formed coalition of opposition forces that the United States helped create. But at a news conference in August, Mr. Obama told reporters that any evidence that Mr. Assad was moving the weapons in a threatening way or making use of them is "a red line for us" that could prompt direct American intervention. "That would change my calculus," he added. That would change my equation. American officials would not say over the weekend whether the activity they were now seeing edged toward the limit set by Mr. Obama. "These are desperate times for Assad, and this may simply be another sign of desperation," one senior American diplomat, who has been deeply involved in the effort to try to dissuade Mr. Assad's forces from using the chemical weapons, said Sunday. A senior Israeli official said the movement of the chemical weapons, and the apparent preparations to use them, could be a bluff, intended as a warning to the West at a moment when NATO and the United States were debating greater support to opposition groups. "It's very hard to read Assad," one senior Israeli official said. "But we are seeing a kind of action that we've never seen before," he said, declining to elaborate. The White House refused to comment on the intelligence reports, which have been shared with senior members of Congress. But a senior administration official, asked about the concerns, issued a new warning to the Syrians. "The president has made it clear that the use of chemical weapons in Syria would cross a red line for the United States," the official said. We consistently monitor developments related to Syria's stockpiles of chemical weapons, and are in regular contact with international partners who share our concern. The Assad regime must know that the world is watching, and that they will be held accountable by the United States and the international community if they use chemical weapons or fail to meet their obligations to secure them. Representative Mike Rogers, a Michigan Republican who heads the House Intelligence Committee, declined to comment on the new intelligence reports but said in a statement late Sunday: "We are not doing enough to prepare for the collapse of the Assad regime, and the dangerous vacuum it will create. Use of chemical weapons by the Assad regime would be an extremely serious escalation that would demand decisive action from the rest of the world. Several months ago, the United States military quietly sent a task force of more than 150 planners and other specialists to Jordan to help the armed forces there to, among other things, prepare for the possibility that Syria would lose control of its chemical weapons. Turkey has asked NATO for two batteries of the Patriot antimissile system, in part as protection against Syrian missiles that might come into Turkish territory. In making their case, the Turks have raised the possibilities that chemical weapons could be used in the warheads. This is not the first time activity at stockpile sites has been detected. Defense Secretary Leon E. Panetta said on Sept. 28 that there had been "some movement" of Syria's chemical weapons stockpiles to put them in more secure locations. "While there's been some limited movement, again, the major sites still remain in place, still remain secure," he said at the time. But the new activity appears to be of a different nature, and officials are no longer willing to say that all the sites remain secure. "We're worried about what the military is doing," one official said, "but we're also worried about some of the opposition groups," including some linked to Hezbollah, which has set up camps near some of the chemical weapons depots. Since the crisis began in Syria and concern has been focused on the country's vast stockpile, the United States and its allies have increased electronic eavesdropping and other surveillance activities of the sites. A senior defense official said that no United States troops had been put on heightened alert in response to the activity, although the Pentagon was prepared to do so, if necessary.