The group that has hacked the City of Johannesburg is demanding a ransom in bitcoin.

The city shut down its billing system as a precautionary measure after it detected a network breach which resulted in unauthorised access to its information system, it said on its Twitter account.

In a message posted on the city’s website, a group called Shadow Kill Hackers is demanding a ransom in 4.0 bitcoins, broadcaster eNCA reported. The hackers have threatened to upload all hijacked data on the Internet by 28 October if their ransom is not met, it said on its website.

The incident is currently being investigated by security experts “who have taken immediate and appropriate actions to reinforce security measures and mitigate any potential impacts”, the city said. The investigation will take 24 hours.  — Reported by Jacqueline Mackenzie, (c) 2019 Bloomberg LP