NATO warns Syria against chemical weapons use

Any use of chemical weapons by Syrian President Bashar al-Assad during the ongoing uprising to overthrow his government will draw "an immediate reaction" from the world community, NATO's chief has said.

Secretary-general Anders Fogh Rasmussen's warning on Tuesday came as Syrian forces continued to hit rebel districts near Damascus, while state media reported that rebel forces had hit a school, killing dozens of children.

"The possible use of chemical weapons would be completely unacceptable for the whole international community and if anybody resorts to these terrible weapons, I would expect an immediate reaction from the international community," Rasmussen told reporters at the start of a meeting of alliance foreign ministers in Brussels.

Barack Obama, the US president, told al-Assad on Monday not to deploy chemical weapons, though he did not specify how the US would respond.

The Syrian foreign ministry has repeatedly denied that it would consider using chemical weapons against Syrians, though it has not ruled out their use in case of foreign military intervention.

Foreign military analysts say that Syria has the capability to produce chemical agents such as mustard gas and sarin, and that it could also produce VX nerve gas.

The meeting of the 28-member Western military alliance's foreign ministers in Brussels follows a request from Turkey to boost its defences along the border.

In a statement, NATO said it had "agreed to augment Turkey's air defence capabilities in order to defend the population and territory of Turkey and to contribute to the de-escalation of the crisis along the alliance's border".

Recent intelligence assessments have indicated Damascus is contemplating using ballistic missiles, potentially armed with chemical warheads.

Speaking after the meeting, Rasmussen told reporters that the foreign ministers had "unanimously expressed grave concerns" about the reports, saying: "Any such action would be completely unacceptable and a clear breach of international law."

He would not give further details on the deployment, but said it would ensure effective protection of Turkey against any missile attack, whether carrying chemical weapons or not.

NATO officials have previously made clear such a move would be purely defensive.

A NATO team has already visited a number of sites in Turkey in preparation for the deployment of Patriot batteries, which could be used to shoot down any Syrian missiles or warplanes that stray over the border.

But analysts say any deployment - possibly supplied by the US, Germany or the Netherlands - could take weeks.

Activists say more than 40,000 people have been killed since the uprising against President Assad began in March 2011. Hundreds of thousands of people have fled the country and another 2.5 million are internally displaced.

Syrian opposition fighters have reportedly made dramatic gains recently, and several government mortar shells - aimed at rebel targets close to the border - have landed across its 900-km (560-mile) border with Turkey.

Although the head of the Arab League Nabil al-Arabi told AFP on Monday that the Syrian government could fall "any time", it still holds the capital, parts of the second city Aleppo, and other centres.