Several of the jihadis were said to be involved in plotting attacks in Europe before they were killed by the aerial bombardment.
Outgoing US Defence Secretary Ashton Carter said that the bombers attacked two ISIS military camps on Wednesday, located about 28 miles south-west of the city of Sirte.
On his last day in office before Donald Trump’s administration takes over, Mr Carter told reporters: “We need to strike ISIL everywhere they show up.
“These strikes were directed against some of ISIL’s external plotters, who were actively planning operations against our allies in Europe.
US airstrikes killed terrorists said to be plotting European attacks
These strikes were directed against some of ISIL’s external plotters
“These were critically important strikes for our campaign and a clear of example of our enduring commitment to destroy ISIL's cancer not only in Iraq and Syria but everywhere it emerges.”
The mission, which dropped around 100 bombs on the African jihadi camps, is thought to have been the last signed off by President Barack Obama who leaves office on Friday.
Two B-2 stealth bombers flew a round-trip of around 34 hours from Missouri to strike the former target outside the coastal city – a former ISIS stronghold until the group was driven out in December.
It was the first time the stealth planes had been used in combat in Libya since March 2011, when they were deployed as part of a campaign to oust former dictator Muammar Gaddafi.
Libya has become increasingly more hostile since the fall of its former leader, with competing governments, rival militias and ISIS seeking to gain territory and influence.
In a statement, Pentagon spokesman Peter Cook said: “The ISIL terrorists targeted included individuals who fled to the remote desert camps from Sirte in order to reorganise.
“They posed a security threat to Libya, the region and US interests.”
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The United States carried out nearly 500 air strikes against ISIS targets in Sirte between August and December.
The fight against ISIS
Fri, November 18, 2016
The battle against ISIS militants (also abbreviated as Daesh, ISIL, IS and Islamic State) continues in the Middle East.
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Forces battle against ISIS
The terrorist group had imposed its barbaric rule on residents and extended its control to about 155 miles of Libya’s Mediterranean coastline.
A statement from Libya’s UN-backed Government of National Accord (GNA) in Tripoli said the strikes were “preemptive steps to foil attempts” by ISIS militants to stage new attacks on Sirte and other areas of the country.
The GNA has received strong backing from President Obama’s administration but has struggled to win support inside Libya.