Photo: The Canadian Press. All rights reserved.

In this Wednesday, Dec. 5, 2012 photo, Free Syrian Army fighters aim their weapons inside an abandoned building during heavy clashes with government forces in Aleppo, Syria. (AP Photo/Narciso Contreras)

Syria sharply criticized NATO's move to deploy Patriot missiles along its border with Turkey, calling the decision "provocative," as the West took a major step toward a possible military role in the civil war.

After getting Cabinet approval, German Defence Minister Thomas de Maiziere told reporters that two German Patriot batteries with a total of 400 soldiers would be sent to the border area under NATO command for one year, although the deployment could be shortened.

The announcement also appeared to be a message to Assad's regime at a time when Washington and other governments fear Syria may be readying its chemical weapons stockpiles for possible use as fighting with the rebels in the capital, Damascus, and other areas intensifies.

U.S. Secretary of State Hillary Rodham Clinton reiterated concerns Wednesday that "an increasingly desperate Assad regime might turn to chemical weapons" or lose control of them to militant groups.

Clinton met with Russian Foreign Minister Sergey Lavrov Thursday in Ireland on Thursday, and the two were scheduled to discuss a way forward in Syria later with the U.N. envoy to Syria, Lakhdar Brahimi.

In Iraq, U.S. Under Secretary of Defence Dr. James Miller reiterated the Obama administration's stance that use of chemical weapons is a "red line." The administration has said their use would bring a U.S. response.

In recent days, U.S. intelligence has detected signs the Syrian regime was moving chemical weapons components around within several sites, according to a senior U.S. defence official and two U.S. officials. This type of activity had not been detected before and one of the U.S. officials said it bears further scrutiny.

Syria's deputy Foreign Minister Faisal Mekdad insisted the deployment of the missile defence system would not affect the determination of President Bashar Assad's government to crush the "terrorists," using the regime's term for rebels fighting to topple the longtime leader.

Mekdad denounced the NATO move and the chemical weapons "chorus" as part of a conspiracy that is possibly laying out the foundations for a military intervention in Syria.

Syria has been careful not to confirm it has chemical weapons while insisting it would never use such weapons against its own people