SAN FRANCISCO, June 22 (Xinhua) -- U.S. tech giant Apple agreed on Friday to launch a service program to fix "sticky" keyboard problems on MacBook or MacBook Pro for free.

Apple acknowledged the fault in one of its products that many users have complained about for some time after they reported that the keys of their laptops either got sticky or stopped working at all.

"Apple has determined that a small percentage of the keyboards in certain MacBook and MacBook Pro models" may exhibit some malfunctions such as letters or characters repeating unexpectedly, not appearing or experiencing "sticky" keys that do not respond in a consistent manner, Apple said in a statement.

"Apple or an Apple Authorized Service Provider will service eligible MacBook and MacBook Pro keyboards, free of charge," which may involve the replacement of one or more keys or the whole keyboard, it added.

Apple has announced a list of nine specific models eligible for the repair, including Retina MacBooks that customers bought in 2015, and MacBook Pros from 2016 onward.

The U.S. tech behemoth promised to refund customers the cost of the repair if they have experienced the problem and already paid for servicing through Apple.