South Africa’s Port of Cape Town has reported a cyberattack that has affected its port operating systems, causing disruption to container operations.

Transnet runs a national freight rail line along with major South African ports, including Port of Cape Town and Durban. The company confirmed that its IT applications experienced disruptions.

The website of Transnet was down on 22 July and displayed an error message.

Currently, the port operator is investigating the cause of the disruption.

Three sources with direct knowledge of the matter told Reuters that Durban, the busiest shipping terminal in sub-Saharan Africa, was also impacted by the cyberattack.

In an email seen by Reuters, Cape Town Harbour Carriers Association said to its members: “Please note that the port operating systems have been cyberattacked and there will be no movement of cargo until the system is restored.”

Last week, the state-owned company suspended services of its ports and national freight rail line due to days of political unrest and violence in some parts of the country.

Responding to a question on whether the cyberattack was connected to the unrest, a government official said: “We are investigating, and when that is confirmed or dispelled we are going to make that announcement. Currently we are treating it as an unrelated event.”

Another source added: “The latest disruption has delayed containers and auto parts, but commodities were mostly unaffected as they were in a different part of the port.”

The cyberattack will lead to backlogs that will take time to clear.

Durban serves as a hub to transport cargo out of Africa, including copper and cobalt mined in the Democratic Republic of Congo and Zambia.

Last month, the national flagship carrier of South Korea HMM reported a cyberattack that affected its email server.