A 45-year-old man was arrested in Britain on Thursday on suspicion of committing war crimes during Liberia's civil wars, police said.
Officers from London's Metropolitan Police war crimes team detained the man, whose name was not released, in the capital and took him into custody.
He was arrested for offences contrary to section 51 of the International Criminal Court Act 2001, which covers genocide, crimes against humanity and war crimes.
"The arrest follows an allegation of offences relating to the first and second Liberian Civil Wars, between 1989 and 2003," the Met said in a statement.
"Officers are currently searching an address in southeast London. Enquiries are ongoing."
An estimated quarter of a million people were killed in the back-to-back civil wars in Liberia, which were marked by the widespread use of mutilation and rape.
Some of the brutal violence was carried out by child soldiers acting for warlords.
