Cameron and Obama discuss Syria crisis

David Cameron and Barack Obama have pledged a “serious response” if Bashar Assad’s Syrian regime is proved to have deployed chemical weapons.

The British Prime Minister and the US President discussed the growing crisis by telephone last night and have ordered officials to examine “all options”.

The talks came amid claims from aid organisations that more than 350 people - many of them children – died due to the effects of neurotoxins this week.

A Downing Street spokesman said the leaders spoke for around half an hour.

“They are both gravely concerned by the attack that took place in Damascus on Wednesday and the increasing signs that this was a significant chemical weapons attack carried out by the Syrian regime against its own people,” he said.

“The UN Security Council has called for immediate access for UN investigators on the ground in Damascus. The fact that President Assad has failed to co-operate with the UN suggests that the regime has something to hide.

“They reiterated that significant use of chemical weapons would merit a serious response from the international community and both have tasked officials to examine all the options.

“They agreed that it is vital that the world upholds the prohibition on the use of chemical weapons and deters further outrages. They agreed to keep in close contact on the issue.”

Mr Obama previously suggested that the use of chemical weapons in Syria would be a “gamechanger”.

But he has stopped short of committing to direct intervention in the troubled country – a step that would risk inflaming tensions with Russia.

Mr Cameron would also face domestic resistance to military action, with Tory MPs already having insisted there should be a Commons vote before arms are supplied to rebels.

However, there is speculation that the US, Britain and France could back limited airstrikes to demonstrate that deployment of chemical weapons will not be tolerated.

Mr Cameron also spoke to Canadian PM Stephen Harper, who agreed that the “international community must respond appropriately”.

Medecins Sans Frontieres said hospitals it supports in Syria treated some 3,600 patients with “neurotoxic symptoms”, 355 of whom died.

It said the patients had arrived in three hospitals in the Damascus area on Wednesday. Staff described people suffering from convulsions, extreme salivation, contracted pupils and sight and respiratory problems.

However, the organisation stressed it could not “scientifically confirm” the use of chemical weapons.