The launch of Samsung's Galaxy Note7 in the UK could be in doubt after reports emerged that replacement handsets still have battery issues that can cause them to catch fire.
Multiple claims from the US say that replacement devices are still suffering from what Samsung had identified as a "battery cell issue" that had been caused by a "rare manufacturing defect".
Samsung has now revealed it is reducing production of the smartphone.
In a statement, Samsung UK said: "We are temporarily adjusting the Galaxy Note7 production schedule in order to take further steps to ensure quality and safety matters."
The tech giant did not comment on the UK release date, which had been moved to October 28 as part of the replacement program.
The technology giant ordered a recall of the device in September, on the eve of its launch in the UK, after more than 30 reports globally of devices overheating.
The Korean manufacturer then began a program offering replacement phones to consumers who had pre-ordered the device in the UK.
Samsung said last month it was "confident" it had completely overcome the problem and was ready to launch the device.
However, concerns have now been raised over further defects within the device, beyond the battery cell, following several reports in the US of phones catching fire that showed the green battery icon Samsung added to replacement phones to mark them as safe.
The company added that 45,000 Note7 devices had been sold in Europe through their pre-order campaign - the majority in the UK - and more than 75% had since been replaced with either a Note7 or another Samsung handset.