Korea's consumer-safety watchdog says it is looking into the safety of Samsung Electronics’ Galaxy Note 7 smartphones amid a series of reports that some Note 7 replacements have caught fire.

An official from the Korean Agency for Technology and Standards(KATS) said on Monday it is unclear when the probe results will be released, but the agency will decide on recalls or other action depending on the results.

There have been eight cases of reported fires involving replacement Note 7s so far --- five in the U.S., and one each in South Korea, China and Taiwan.

The results of investigations into the seven cases outside South Korea have yet to be announced. The Korea Testing Laboratory and SGS Korea, which conducted a probe into one incident in South Korea, concluded that the fire was caused by a "strong external shock or being crushed."