For the US, the problem is that Obama has called this a red line. His party does not want any intervention in Syria. If it is proved that the regime fired these types of weapons then King Obama will be forced to take a stand - not necessarily engage. His trip to your country will be interesting for the conservatives here in the US to observe.
U.S. confirms ISIS computer expert killed in air strike (Reuters)
from the article: U.S. looking into allegations of chemical weapons use in Syria