The U.S. Intelligence Community intercepted communications in which the Syrian military is heard planning the chemical weapons attack that took place last week. From CNN:

The US military and intelligence community has intercepted communications featuring Syrian military and chemical experts talking about preparations for the sarin attack in Idlib last week, a senior US official tells CNN.

The intercepts were part of an immediate review of all intelligence in the hours after the attack to confirm responsibility for the use of chemical weapons in an attack in northwestern Syria, which killed at least 70 people.

So far, no intercepts indicate that Russia had any direct involvement or advance knowledge of the attack, but CNN’s source suggests this may be because the Russians are more wary of having their communications intercepted. At a briefing, the source told CNN, “We know the Russians have chemical expertise in-country.” However, the source would only say the U.S. was still “assessing” Russian involvement.

Monday an unnamed government source told the Associated Press Russia knew about the attack in advance. That judgment was based on the presence of a Russian drone over a hospital where victims of the attack were treated. There was subsequently an airstrike on that hospital in what the U.S. believes was an attempt to cover up the use of chemical weapons. The AP’s source suggested the drone and the later bombing were too much of a coincidence and must indicate Russian complicity in the attack.

President Trump sounded less certain when he was asked if Russia knew about the attack. “I would like to think that they didn’t know, but certainly they could have,” the President said Wednesday. He added, “We’ll find out.”

Here’s CNN’s report on the intercepts: