"Worrying signs" seen in "the last few days" suggest Syria might be looking to put its stockpile of chemical weapons to use, an anonymous high-ranking U.S. official told CNN on Sunday.
"There are concerns the regime may be considering use of chemical weapon," the source said, cautioning that a concrete determination regarding the developments has not been made in Washington.
The fresh concerns about Syria's chemical arms are not "just about movement [of warfare materials], but about potential intent to make certain chemical weapons ready for use," according to the official, who added it is not apparent whether the detected activity has been personally authorized by besieged Syrian dictator Bashar Assad or what might be the ultimate intention.
The Syrian military is understood to keep its stock of hundreds of tons of blister and nerve agents in different locations from the missiles and other munitions that would be used to disperse the materials.
There have been broad concerns during the 20-month uprising against Assad that the government might put its chemical arsenal to use or allow components of the stockpile to fall into extremists' hands.
The activities by Assad forces led the United States and partner governments to issue new warnings of the consequences that will come if Damascus crosses the red line and employs chemical weapons against domestic opposition forces, the New York Times reported on Sunday.
The new cautionary messages were "deliberately vague to keep Assad guessing," according to one European official, and were transmitted by Russia and other third parties.
The Syrian military this summer was understood to have relocated some of its chemical arsenal away from scenes of fighting. That action was largely understood to be aimed at protecting the unconventional weapons. This time, though, "the activity we are seeing suggests some potential chemical weapon preparation," a U.S. official told the newspaper.
In his warning to Assad this summer, President Obama said, "a red line for us is we start seeing a whole bunch of chemical weapons moved around or being utilized." His statement suggested that such a development could lead to military intervention by the United States or other nations. Officials this weekend would not clarify if the detected chemical movements are verging on the red line spelled out by Obama.
Syria has pledged not to use its chemical arsenal against opposition forces but has suggested it might be used to ward off a foreign military intervention.
"These are desperate times for Assad, and this may simply be another sign of desperation," an informed high-ranking U.S. envoy told the Times on Sunday.
A high-ranking Israeli official said the seeming evidence of chemical weapons preparations could be a ruse to scare Western governments into backing off plans to provide greater assistance to Syrian rebels. "It's very hard to read Assad. But we are seeing a kind of action that we've never seen before," the official said.
The Obama administration would not address the latest intelligence, which has been made available to high-ranking U.S. lawmakers. An anonymous Obama official said, "the president has made it clear that the use of chemical weapons in Syria would cross a red line for the United States. We consistently monitor developments related to Syria's stockpiles of chemical weapons, and are in regular contact with international partners who share our concern."
A few months ago, the U.S. Defense Department deployed in excess of 150 military advisers to assist the Jordanian government in planning for the fallout of a chemical weapons crisis. The United States and other NATO countries are working with Turkey to address its call for air-defense support to defend against feared firing of Syrian ballistic missiles armed with chemical warheads.
Ankara has requested that NATO members deploy two Patriot missile batteries near its lengthy border with Syria, according to the Times.
Turkish officials informed the London Guardian newspaper that their government had acquired reliable intelligence that Assad could authorize chemical strikes in the event regime air forces are unsuccessful in curbing the advancement of rebel forces.
Ankara believes Syria's Scud and SS-21 missiles would mostly target rebel-held territory but that some missiles might unintentionally land in Turkish territory, as has already been the case with Syrian-fired mortars and artillery rounds.
"We have intelligence from different sources that the Syrians will use ballistic missiles and chemical warheads. First they sent the infantry in against the rebels and they lost a lot of men, and many changed sides. Then they sent in the tanks, and they were taken out by anti-tank missiles," a high-ranking Turkish official said. "So now it's air power. If that fails it will be missiles, perhaps with chemical warheads. That is why we asked NATO for protection."
U.S. Secretary of State Hillary Clinton on Monday said "we have made our views very clear. This is a red line for the United States," the Associated Press reported. "I'm not going to telegraph in any specifics what we would do in the event of credible evidence that the Assad regime has resorted to using chemical weapons against their own people. But suffice it to say, we are certainly planning to take action if that eventuality were to occur."
While condemning the violent actions of Damascus that have already caused tens of thousands of deaths, Clinton said "there is no doubt that there's a line between even the horrors that they've already inflicted on the Syrian people and moving to what would be an internationally condemned step of utilizing their chemical weapons."
Clinton is said to be optimistic a decision will be made this week on NATO's intention to provide Turkey with Patriot missiles, Reuters reported on Monday.
A high-ranking State Department official told reporters Washington was hopeful "that the three contributing countries that are being considered -- the United States, Germany, and the Netherlands -- will be in a position" to deploy their Patriot interceptors in Turkey.
The anonymous official said it would likely be "at least a matter of weeks" before any actual missile fielding occurs, given the time needed for relevant domestic legislatures to authorize the weapon deployments.
The Syrian Foreign Ministry on Monday insisted there were no plans for chemical attacks and accused Washington of raising a false alarm around the issue, the Xinhua News Agency reported.
"Syria has repeatedly stressed to the American side directly, or through the Russian friends, that it will not use such weapons, even if they existed, against its people under any circumstance," the statement read. Damascus has never made a public declaration of the chemical arsenal though its possession of such is widely understood as fact.
Israel has on two occasions since October sought "permission" from Jordan to conduct airstrikes against Syrian chemical arms sites, the Atlantic reported on Monday. Amman has not yet replied affirmatively to the request, which can be seen as something of a formality; Tel Aviv proved in its 2007 attack on the suspected Dair Alzour nuclear site that it is willing to take unilateral action against Syria.
Israeli and U.S. unmanned aerial vehicles are being used to monitor Syrian sites believed to hold chemical arms, according to insiders.