At his press conference on Thursday following a summit with Gulf leaders, President Obama was asked why he has not taken action — both in 2013 and today — against the Assad regime’s use of chemical weapons against civilians.

Obama initially pushed aside the question about the August 2013 attacks near Damascus in which up to 2,000 people died, either at the time or subsequently from the effects of sarin. He then explained that the US had not needed to intervene after up to 2,000 people died from attacks near Damascus in August 2013 because “Assad gave up his chemical weapons”.

As for subsequent attacks with chlorine, including use in Idlib Province in northwest Syria in March and April, Obama said that “chlorine is not historically a chemical weapon”.

The reason that I am here is not because of what happened in Syria a couple of years ago….

My commitment was to make sure Syria is not using chemical weapons and mobilize the international community to assure that would not happen. We positioned ourselves to be willing to take military action: the reason we did not because Assad gave up his chemical weapons….

It is true that we have seen reports about the use of chlorine in bombs that had the effect of chemical weapons.

Chlorine itself historically has not been listed as a chemical weapon, but when it is used in this fashion, [it] can be considered a prohibited use of that particular chemical. And so we are working with the international community to investigate that.

In fact, if we have the kinds of confirmation that we need, we will once again work with the international community and the organization charged with monitoring compliance by the Syrian Government and we will reach out to patrons of Assad, like Russia, to put a stop to it.