A Samsung smartphone advertised as being water-resistant has failed a water immersion test by a leading product review site.
The Samsung Galaxy S7 Active stopped working after being put in a tank that simulated the effect of being about 5ft (1.5m) underwater.
Consumer Reports repeated its test on a second model, which was also damaged.
Samsung said it was possible defective devices were “not as watertight” as they should have been.
When removed after half an hour, the first phone’s display was non-responsive and marred by green lines. Bubbles had also formed in its two camera lenses.
The second handset subjected to the same test suffered similar faults.
Samsung’s website stated the Galaxy S7 Active, which is sold in the US but is not available in the UK, is IP68-certified.
The international protection rating signifies the phone can withstand “continuous immersion in water”.
Consumer Reports made headlines six years ago when it flagged a problem with the iPhone 4’s antenna before Apple had acknowledged the issue.
Last year Sony warned owners of its waterproof Xperia smartphone range against using the devices underwater.
“The IP rating of your device was achieved in laboratory conditions in standby mode, so you should not use the device underwater, such as taking pictures,” advice on its water and dust protection page states.
Samsung is expected to report its most profitable quarter in more than two years thanks to strong sales of the Galaxy S7 range.