A US air strike on a "jihadist" training camp in Libya killed dozens of people Friday, probably including a senior ISIL group operative behind attacks in Tunisia, officials said.

A US air strike on a "jihadist" training camp in Libya killed dozens of people Friday, probably including a senior ISIL group operative behind attacks in Tunisia, officials said.

Pentagon press secretary Peter Cook said Noureddine Chouchane, also known as "Sabir," and other "jihadists" had been planning attacks against American and other Western interests.

"We took this action against Sabir in the training camp after determining that both he and the ISIL fighters at these facilities were planning external attacks on US and other Western interests in the region," Cook said, without providing specifics.

"We see what's happening in Iraq and Syria and we believe that these fighters in Libya posed a threat to our national security interests."

It was the second US air raid in the violence-wracked North African country targeting the fast-expanding "jihadist" group in the past three months.

The strike early Friday near the city of Sabratha "likely killed" ISIL operative Chouchane, a US official said earlier.

Britain's defense ministry said the strike on the camp was carried out from a Royal Air Force base, RAF Lakenheath.

"I was satisfied that its destruction makes us all safer, and I personally authorized the US use of our bases," Defense Secretary Michael Fallon said in a statement.

A "jihadist" safe house was destroyed in the dawn raid about 70 kilometers (42 miles) west of Tripoli, according to Hussein al-Dawadi, an official in Sabratha near the border with Tunisia.

"The raid killed 41 people who were all inside the house," Dawadi told AFP. "The vast majority of those killed were Tunisians who were probably members of ISIL."

Cook would not confirm the figure but said a "significant" number was dead, and that as many as 60 people had been known to use the camp.

A suspect wounded in the strike said he had been taken there blindfolded for combat training, Dawadi added.