The US did not inform the Libyan government about the arrest of the suspected ringleader of the 2012 on an American diplomatic compound, according to a Libyan minister.
The US Ambassador to the United Nations, Samantha Power, notified the UN Security Council of the capture on Sunday of Ahmed Abu Khatallah by US special forces.
She said an investigation had not only implicated him in the 2012 raid but also planned "further armed attacks" against US personnel.
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Kim Wall, whose body had been cut apart, is believed to have died while on a privately built submarine belonging to a Danish inventor.
Parts of Scotland and northern England will start the day with outbreaks of thundery rain before it slowly clears through the day.