Arriving for a Nato foreign ministers' meeting in Brussels, William Hague, the UK Foreign Secretary, said that Britain had delivered a stark message to Bashar al-Assad, echoing the words of the Obama administration on Monday.
"We are worried about chemical weapons," said Mr Hague. "We have become more concerned about them in recent days for the same reasons the US has."
The US administration is believed to have satellite images showing the movement of materials for chemical weapons.
Mr Assad's regime is known to possess sarin nerve gas, and Riad Kahwaji, the head of the Institute for Near East and Gulf Military Analysis, said suspicious movements had been detected in the past few days.
"We are dealing with a regime that has not hesitated to use the heaviest weapons it has. It has to be taken very seriously when we see that it is moving around chemical weapons," he said.
The request is believed to have come after intelligence assessments concluded that Mr Assad's regime, now under severe pressure from the rebel Free Syrian Army which has penetrated Damascus, could resort to firing its arsenal of Scud ballistic missiles at neighbouring states.
In extremis, these weapons could carry chemical warheads. "We know (Syria has) chemical weapons and this is also the reason why it is necessary to ensure effective defence and protection of our ally Turkey," said Anders Fogh Rasmussen, the Nato secretary-general.
Russia, Syria's staunchest ally, warned against the deployment. "Creating additional capabilities on the border does not defuse the situation but on the contrary exacerbates it," said President Vladimir Putin. (© Daily Telegraph, London)