Senior US military officials say the massive airstrikes that killed more than 80 Islamic State militants in southern Libya last month generated critical computer data, documents and information from prisoner interrogations that the US can use to track and target more fighters.

Marine Gen. Thomas Waldhauser, the head of US Africa Command, told The Associated Press in an interview on Friday that the US obtained significant intelligence from the camps after the bombings, adding “there are some things we’re working on”. He declined to go into detail about the intelligence that was gathered. But a senior US military official described some of the information gathered and said that several Islamic State fighters who survived the 18 January strikes had been taken for interrogation by forces from Libya’s Government of National Accord.

The official said the intelligence collected at the IS camps confirmed that the fighters had direct communication with the core Islamic State group in Syria and provided information on how they move through tunnels in the country. The official was not authorised to discuss the details publicly, so spoke on condition of anonymity.

“We did get some actionable intelligence and we continue to work with that and develop what we can from it,” Gen. Waldhauser told The Associated Press at the Munich Security Conference, which began on Thursday. “We are watching, we are paying attention to where we can see numbers of them gathering and that – to a large degree – is the focus of our intelligence development.”

US Air Force B-2 bombers attacked Islamic State military camps in Libya’s lawless southern region, targeting fighters who former Defence Secretary Ash Carter said “were actively planning operations against our allies in Europe”. The senior US military official said that none of the information appeared to suggest an imminent attack against the West.

In addition to the Libyan militia troops, special operations forces from the United Kingdom had taken part in the intelligence collection, according to the military official, who said that all the IS members in the camps were foreign fighters and none were Libyan.

Gen. Waldhauser said the military had been watching the camps since late last autumn but that the fighters move around southern Libya and do not stay anywhere for long.

He called the strike a ‘devastating blow’ to the group. “It was successful from the standpoint that we really did, I think, send a very strong signal to the ISIL that remains in Libya that we will watch you and we will come after you,” the general said, using another acronym for Islamic State.

The General said that the foreign fighter flow across the porous borders of the countries surrounding Libya, including Chad and Tunisia, continues to be a concern. Overall, he said, there are still “a couple of hundred” IS members left in Libya. The total had been well over 5,000 last year, but that number began to fall as Libyan forces, backed by US airstrikes, began to successfully push them out of the central coastal city of Sirte.

Libyan forces ousted the last IS militants from their holdouts in Sirte in December.

During the January airstrikes by the US, the B-2 bombers flew more than 30 hours round-trip missions from Missouri and dropped about 100 precision-guided munitions. It was an unusual mission since the US does not often send the bombers on counterterrorism strikes.

The bombings, which also included strikes by Air Force MQ-9 Reaper drones, destroyed a lot of the camps, and probably a lot of potential intelligence information. The camps were about 45 kilometres southwest of Sirte.

It also was the first time the B-2s had been used in combat since the 2011 air campaign that forced Libyan dictator Moammar Gaddafi from power and led to his killing.

Libya plunged into chaos and lawlessness after Gaddafi’s removal and the subsequent civil war. Two rival administrations operate in the east and west of the vast, oil-rich nation.