(Reuters) – South Africa’s labour court ordered ArcelorMittal South Africa Ltd employees to stop working at its steel plants blast furnaces, coke batteries, and blast furnaces. This was after ArcelorMittal claimed these were essential services that are prohibited from striking under law.

Following the breakdown of wage negotiations last week, Wednesday saw the National Union of Metalworkers of South Africa (NUMSA), which began a walkout at Africa’s largest steel producer.

ArcelorMittal stated Wednesday that it approached the court in an effort to expel certain workers from strike. The company cited South African labour law.

NUMSA released a statement saying that Justice Mahosi from the Labour Court temporarily stopped the strike, but it was not for the workers at blast furnaces or coke batteries, and only until the final judgment had been reached.

“This is because only employees in those departments can take part in the strike while all workers are allowed to.”

The union demands a 10% increase in pay, housing allowance, and payment for 80% of the medical costs. This is against the final offer by the company of a 7% increase.

ArcelorMittal could not be reached immediately for comment.

Although a NUMSA spokesperson stated she couldn’t immediately determine how many union members were working in the affected areas, she said that NUMSA was ArcelorMittal’s biggest union and had about half the permanent workers affiliated with it.

According to the company’s latest annual report, 7,133 employees were employed by ArcelorMittal SA in Luxembourg, which is majority-owned by ArcelorMittal SA.