Meanwhile Another of Abedi's sons and brother to the Manchester bomber, Hashem, was detained on Tuesday evening in Tripoli on suspicion of links to Islamic State, said Ahmed Bin Salem, a spokesman for the Special Deterrence Force.

"We have evidence that he is involved in Daesh (Islamic State) with his brother. We have been following him for more than one month and a half," Bin Salem said. "He was in contact with his brother and he knew about the attack."

Salem said Hashem, 20, had traveled from London to Tripoli on April 16.

British interior minister Amber Rudd said earlier that the bomber had recently returned from Libya. Her French counterpart Gerard Collomb said the man had links with Islamic State and had probably visited Syria as well.