Unidentified assailants set fire to five trucks on a key trade corridor in South Africa July 10, the second such attack in as many days.

The attackers torched vehicles July 10 on the N4 highway that links the commercial hub of Gauteng to the Port of Maputo in neighboring Mozambique, police spokesman Brigadier Selvy Mohlala told Johannesburg-based broadcaster Newzroom Afrika. The route is a key corridor for coal and chrome exports from South Africa.

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On July 9, assailants set ablaze trucks on the N3 highway that links Gauteng to the Port of Durban, Africa’s biggest container harbor.

5 trucks have been set alight on the N4 in Mpumalanga. Authorities say the vehicles were torched after an accident near Waterval Boven in the early hours of this morning. @XoliMngambi speaks to All Truck Drivers Foundation Secretary General Sifiso Nyathi.https://t.co/J45Lrgbh3d pic.twitter.com/0No614DYOy

— Newzroom Afrika (@Newzroom405) July 10, 2023

Truckers regularly block major arterial roads in South Africa to protest the hiring of foreigners. The demonstrations threaten trade and employment because 80% of all goods moved in and around South Africa are ferried by road, according to the Road Freight Association.

The ongoing attacks have led some companies to move their cargo through the ports of neighboring countries instead of South Africa.

The latest incidents come after South Africa was rocked by seven days of violence in 2021, the worst instance of civil unrest since the advent of multiracial democracy in 1994. The N3 was shut down and shops were looted during the violence that led to the deaths of more than 350 people and cost the economy an estimated 50 billion rand ($2.7 billion). The orchestrators of the unrest have yet to be prosecuted.

President Cyril Ramaphosa expressed concern July 9 about the attacks that have “a negative impact on our economy,” he told reporters after a meeting of the governing African National Congress’s top leaders.

“It’s almost like economic sabotage because burning six trucks on the main artery of our country in terms of the economy is concerning,” he said.

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The N3 highway was closed for most of July 9 as mop-up operations began. The police have not yet made any arrests following the attacks.

“The targeted precision of the attack is worrying,” the Road Freight Association said. “This was well planned and efficiently implemented. At this point, no group has acknowledged that they are responsible.”