Taiwan Semiconductor Manufacturing Co. (TSMC), which makes chips for Apple's iPhones, suffered a computer virus outbreak and warned it could cause shipment delays as well as hit revenue.

The issue, which occurred on August 3, was publicly disclosed Saturday and affected a number of computer systems and so-called fab tools that are required in the chip-making process. TSMC said that there could be delays to product shipments, adding that it would reduce third quarter revenue by 3 percent, or $255 million, from its previous guidance.

On Sunday, the company said that 80 percent of its impacted tools had been recovered and that all issues would be resolved on Monday.

TSMC said most of its customers have been notified but did not specify who it had contacted.

Apple is one of TSMC's major customers. The Taiwan semiconductor firm produces Apple's A11 processor that is currently in the iPhone X. And it is currently making the next-generation A12 processor that is expected to be in the U.S. technology giant's upcoming smartphones. Apple is rumored to be releasing three new iPhone models later this year.