Local and French forces led the hostage rescue operation at a hotel in Mali on Friday, but classified documents reviewed by NBC News show U.S. special forces have been in the country for some time to assist counterterrorism operations.
Terrorists killed dozens when they attacked the Radisson Blu hotel in Bamako before soldiers swept in and ended the siege.
ISIS is not believed to be behind the attack, a senior U.S. intelligence officer told NBC News. There are other militant groups operating in the area -- al Qaeda in the Maghreb (AQIM), northern Malian Taureg rebel groups, and Ansar ad-Din -- and one Taureg group has reportedly already claimed responsibility.
U.S. Africa Command said a small team of American special operations forces assisted with evacuating hostages -- a sign of the counterterrorism and military aid program the U.S. has been running in Mali since 9/11.
Briefing documents from 2013 and 2015 reviewed by NBC News detail the American attempt to battle terror groups in the country, and its results.
A 2013 post-graduate study by a U.S. Army major -- a former special operations trainer in Mali --criticized the effort as scattershot and deemed it "anything but a successful strategy."
"Training that was episodically provided rarely diffused or even took hold," his study concluded. "If one were to count up the dollars spent and events participated in, a lot of effort was expended. But what all these efforts added up to was not consistently focused over the long term."
The end result, the study said, was that an opportunity to revamp the Malian army was largely wasted.
"There was no concerted effort by [special operations forces] or anyone else to build the capability of the Malian Army writ large," it said.
U.S. security cooperation in Mali after 9/11 centered on efforts to combat al Qaeda.
"Black" special operators began scouting locations and targets as early as 2002. So-called "white" special operations from the Army, Navy and National Guard also deployed numerous times for training and operation.
At a 2011 conference in the region, U.S. intelligence noted both the Malian president's "apathetic" attitude towards AQIM and an impending crisis generated by armed Tuaregs' return to northern Mali, according to a U.S. officer directly involved in special operations planning.
In September 2011, as the Gadhafi regime was collapsing in Libya, Tuareg fighters began to cross into Mali after emptying several Libyan arms depots.
By March 2012, Mali's president had been overthrown in a military coup. U.S. special operations activity shrank dramatically because of a law preventing support to non-democratically elected governments.
Control of much of northern Mali fell in early 2012 to al-Qaeda-linked jihadist groups long concentrated in the area, triggering a French counterterrorism operation and its U.S. counterpart, codenamed "Juniper Micron." The U.S. special forces are still in Mali, according to a recent classified briefing.
France deployed troops to Mali in January and began a significant around-the-clock air campaign in the north directly supported by the United States - including a command team deployed to French headquarters, a refueling squadron providing aerial support to French aircraft, and 24 tons of equipment.
The U.S. Joint Special Operations Command also quietly deployed to Mali to work with French counterparts and go after high value al Qaeda targets.
According to the most recent U.S. intelligence documents, the American Embassy in Bamako has been beefed up with new intelligence activities - and a counter-propaganda operation. A team deployed in 2008 produced and broadcast a 60-episode radio serial drama in four languages to reach different ethnic groups.