Transcript for New information on the deadly ambush in Niger

tonight in Niger uncovering new details about the deadly attack on those four American special ops soldiers ambushed and killed what was their original mission? ABC's senior foreign correspondent Ian Pannell tonight. Reporter: Tonight, ABC news has learned the target of that deadly mission that killed four U.S. Soldiers. Sources tell us, his name is doundou cheffou, a key ISIS operative, one of the most dangerous terrorists here in Niger. This picture obtained by ABC news is the only known image of the man code-named Naylor road. Local officials are now convinced he was one of the ringleaders of the ambush. And now a major revelation. Sources telling ABC news it wasn't a reconnaissance mission, as the Pentagon still insists. Here in Niger, we met a senior officer who was on that raid who asked we don't use his name. He says, "It wasn't an intelligence mission, we were sent there to get doundou." During the operation, sourcing tell us anxious Nigerian officers asked for reinforcements and more weapons, but they say American officers turned them down. So, they didn't want to get reinforcements? He says he offered to get help, but was told it would be a waste of time, because they'd lose their target. U.S. Intelligence sources telling ABC news the American soldiers also voiced the same concerns when they were told support troops were no longer coming. Hours later, the mission going tragically wrong. And Ian Pannell on the ground in Niger. You are now reporting that sources are telling you that this was never a reconnaissance mission, that they were targeting that key ISIS operative all along. What's the Pentagon saying about that? Reporter: Yeah, that's right, David. Tonight, the Pentagon still sticking to its guns, insisting that this was only a reconnaissance mission. And Ian, you learned tonight from some of your sources that several vehicles from the mission may have fallen into enemy hands, including some sensitive equipment? Reporter: That's right. Knee gear Yan officials claim the terrorists were able to capture two American vehicles, and crucially, a third vehicle, which sources say contained secret CIA supplied surveillance equipment.

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