Most of the trucks attacked over the past week were transporting coal and chrome.

Police made the revelation as it provided an update on their plan to put an end to these attacks.

More than 20 trucks have set alight in KwaZulu-Natal, Mpumalanga and Limpopo.

The motive for the attacks is still unclear at this stage. But police are looking at various possibilities. It includes a section of the freight industry still upset about the hiring of foreign nationals as truck drives and whether rival companies are fighting over transportation contracts.

The army has been roped in to patrol key routes.