China Railway Corp said on Friday that it had replaced all cables provided by a company found to be supplying substandard product that might ignite and release toxic gases.

"We always make transport safety the priority. We have replaced all cables provided by Shaanxi Aokai Cable Co," the country's top railway operator said in a statement on Friday.

The railway operator said that after it learned from media reports that the company's cables had been found to be substandard, it immediately investigated which rail lines used the products.