Eight men in England and Scotland have been arrested after several US celebrities reported their phones had been hacked, the UK National Crime Agency (NCA) says.
The suspects are accused of working together to access the phones of influencers, sports stars, musicians and their families last year, the NCA said.
The names of the victims were not released.
The men aged 18 to 26 were arrested on Tuesday, according to Europol, and could face charges of computer misuse act offences and money laundering.
The NCA said victims' phone numbers were taken over by hacking their SIM cards, allowing criminals to control the victims' apps remotely.
Money and personal information such as contacts were stolen from the targets.
According to Europol, criminals stole more than $US100 million ($A129 million) in cryptocurrencies.
The criminals also posted content and sent messages masquerading as the victims.
The targets' SIM cards were deactivated and the allocated numbers imported onto other SIM cards in a process known as "SIM swapping," the NCA said.
Two individuals were previously arrested in Malta and Belgium in connection with the case, according to Europol.
The investigation involved the NCA and law enforcement agencies from the United States, Canada, Belgium and Malta.