A senior congressional aide who has been briefed on the deaths of four U.S. servicemen in Niger says the ambush by militants stemmed in part from a “massive intelligence failure.”

The Pentagon has said that 40 to 50 militants ambushed a 12-man U.S. force in Niger on Oct. 4, killing four and wounding two. The U.S. patrol was seen as routine and had been carried out nearly 30 times in the six months before the attack, the Pentagon has reported.

The aide, who spoke on condition of anonymity because he is not authorized to speak publicly, said the House and Senate armed services committees have questions about the scope of the U.S. mission in Niger, and whether the Pentagon is properly supporting the troops on the ground there.

There was no U.S. overhead surveillance of the mission, he said, and no American quick-reaction force available to rescue the troops if things went wrong. If it weren’t for the arrival of French fighter jets, he said, things could have been much worse for the Americans.

Congress also has many unanswered questions about what happened, he said, including about the specifics of the mission that day and the accounts lawmakers have been given about the timeline of the attack and rescue.

The aide said questions are being asked about whether the U.S. soldiers were intentionally delayed in the village they were visiting. He said they began pursuing some men on motorcycles, who lured them into a complex ambush. The enemy force had “technical” vehicles — light, improvised military vehicles — and rocket-propelled grenades, the official said.

After the rescue when it became clear that one soldier was missing, “movements and actions to try and find him and bring him back were considered. They just were not postured properly [to get him].” The body of Sgt. La David Johnson was not recovered until nearly 48 hours after the Oct. 4 attack.

A Pentagon spokesperson called the claim of an intelligence failure “speculation.”

“An investigation is underway,” said the spokesperson. “At the conclusion of the investigation, we will provide further details.”

On Thursday, Director of the Joint Chiefs of Staff Lt. Gen. Kenneth McKenzie said that “every tactical engagement doesn’t necessarily proceed from an intelligence failure. We’ll look at it and we’ll come to conclusions about how intelligence could have supported adequately or inadequately the engagement that occurred. But on a battlefield, the enemy gets a vote.”

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SOURCE: NBC News, Ken Dilanian and Courtney Kube

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