WASHINGTON: The United States is looking into whether Russia was complicit in an alleged chemical weapons attack by the Syrian military on civilians, but has not yet made a determination, a senior administration official said on Tuesday.
The official said the US was continuing to gather intelligence on whether Russian forces in Syria were aware of the regime's plans, and whether they participated in the suspected chemical attack on a rebel-held town that left at least 87 dead.
But the official suggested Washington believed Russia at least knew in advance.
"How is it possible that their forces were co-located with the Syrian forces that planned, prepared and carried out this chemical weapons attack at the same installation and did not have foreknowledge?" said the official, speaking on condition of anonymity.
"We do think it is a question worth asking the Russians," the official added.
"We've seen these militaries operate very closely, even down to an operational level," he said, adding: "There is not a consensus on our side about the extent (of that cooperation) or how to interpret the information we have and continue to get."
A second senior US administration official accused Russia of embarking on a misinformation campaign designed to "confuse the world" about last week's alleged attack on Khan Sheikhun.
Speaking on condition of anonymity to discuss sensitive intelligence matters, the official said that Moscow was systematically trying to deflect blame away from the regime and onto rebels and the Islamic State group -- against all evidence.
The official added that US intelligence does not believe that the Islamic State group has sarin, the powerful chemical agent Washington is "confident" was used against the rebel-held town.