The younger brother of the Manchester bomber has said Salman Abedi was radicalised online in Britain, according to Libyan counter-terrorism forces.
A spokesman said Hashem Abedi said he bought equipment for the attack in Britain but he didn't know where the attack would be carried out.
Ahmed Bin Salem, a spokesman for Tripoli's Special Deterrence Force, told Reuters: "Hashem said that he and Salman got the ideology of Daesh (Islamic State) in Manchester in 2015 from the internet and some friends in the UK.
"He added that they used to watch videos and had sympathy for children in Syria and wanted to do something for Daesh to help."
Salman and Hashem flew to Libya on April 18, Bin Salem said. Salman traveled back to Manchester about a week before the attack, after telling his parents he was going on pilgrimage to Mecca.
"Hashem said that he bought all the necessary things for Salman for the attack from the UK and added that Salman was planning to carry out an attack but he did not know where," Bin Salem said.
He said Salman Abedi also phoned Tripoli on May 15 before carrying out the attack to "say goodbye to his family before the attack".
Officials previously said Hashem was planning his own "terrorist act" in Tripoli.