AFP — Major ports handling 40 percent of Australia’s freight trade have resumed operations, leading operator DP World said Monday, three days after they were crippled by a cyberattack.

DP World cut its systems from the internet when the attack was detected Friday, preventing trucks from unloading or picking up cargo at ports in Sydney, Melbourne, Brisbane and Fremantle.

“DP World Australia is pleased to announce that operations resumed at the company´s ports across Australia,” the operator said in a statement.

It said it expected to move 5,000 containers out of the four terminals during the day — not far from industry estimates of their usual daily traffic.

Investigations and efforts to protect systems may still cause “some necessary, temporary disruptions” to port services in the coming days, the company said.

DP World said its investigation and remediation work were likely to take “some time”.

DP World’s advisor on its response to the cyberattack, Alastair MacGibbon, said there had been “unauthorised activity in the system”.

Data had been taken by “someone malicious or unauthorised”, he told Nine Network television, without giving details of the nature of the stolen information.