Western powers are considering air strikes against president Bashar al Assad’s military assets in Syria in the near future, in a move aimed at warning the regime not to deploy chemical weapons.

Syria yesterday bowed to international pressure and agreed to let UN inspectors gain access to sites in the Damascus suburbs where alleged chemical attacks occurred last week.

But the move was quickly rebuffed by the US, with the Obama administration criticising it as “too late to be credible” in a further sign that the case for military action against Syria was building. The White House also said there was “very little doubt” that chemical weapons were used in last week’s attack on east Damascus, which the Syrian regime has denied. More than 300 were killed and thousands injured in the attack.