Detectives from the UK's South East Regional Organised Crime Unit (Serocu) have arrested two men this morning (22 June) in Lincolnshire and Bracknell for conspiracy to gain "unauthorised access" to the computer networks of US tech giant Microsoft.
A 22-year-old man from Lincolnshire was arrested on suspicion of hacking into a computer and a 25-year-old man from Bracknell was arrested under computer misuse act offences.
The unnamed pair currently remain in custody.
While it is still unknown what systems were targeted, police confirmed the activity was part of a larger, global, operation which took place earlier this year.
"This group is spread around the world and therefore the investigation is being coordinated with our various partners," said detective sergeant Rob Bryant from Serocu's cybercrime unit.
"We've made two arrests in the UK this morning and have seized a number of devices.
"We are still in the early stages of this investigation and will work with our partners to ensure that cybercriminals have no place to hide.
"It is too early to speculate on what information the group have accessed, however, after speaking with Microsoft we can confirm they did not gain access to customer information."
The offences took place between January 2017 and March 2017, the authorities revealed.
UK law enforcement is working with the East Midlands Special Operations Unit (Emsou), Microsoft's cyber team, the FBI, Europol and the National Crime Agency's cybercrime unit (NCCU) to investigate these offences and bring culprits to justice.
Serocu has said no further information could be released at this stage.
Earlier this month, Europol announced multiple arrests had been made as part of an international crackdown on the underground sale of tools used to evade anti-virus software.
In the UK, four arrests were carried out between 5 June (Monday) and 9 June (Friday) at addresses in the eastern region, as well as in Wales, Yorkshire and Humber and the South East.
British officers also conducted 31 'cease and desist' visits to young people who were first time offenders, or on the fringe of offending, as part of the operation.