Story highlights One official told CNN that the military's intelligence said it was "unlikely" that the team would run into enemy forces

Military officials have acknowledged that the incident is under investigation and that security procedures are being reviewed

(CNN) CNN has learned new details about Wednesday's ambush in the northwest African country of Niger, an attack that left four US soldiers dead and two wounded.

The new information comes from preliminary after-action interviews that US military officials conducted with survivors of the firefight, information that was shared with CNN by a US defense official.

The Green Beret-led team said that they had just completed a meeting with local leaders and were walking back to their unarmored pick-up trucks when they began taking fire from small arms, machine guns and rocket-propelled grenades.

Some of the soldiers who attended the meeting with local leaders said that they suspected that the villagers were delaying their departure, stalling and keeping them waiting, actions that caused some of them to suspect that the villagers may have been complicit in the ambush, according to the defense official.

While the soldiers were attending the meeting with the local village leadership, the rest of the 12-man team was waiting outside, guarding the vehicles that the US troops were using. The ambush by some 50 ISIS affiliated fighters took place while the two groups of US soldiers were still separated, meaning it occurred during what one official described as their "most vulnerable point."

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