Samsung has stopped global sales of the Galaxy Note 7 and is urging owners of the smartphones to turn them off while it investigates reports of fires.
Complaints of exploding batteries sparked the recall of 2.5 million devices last month.
The South Korean tech giant later assured customers that all replaced handsets were safe.
But reports have emerged from the US of two instances when new and reconditioned Galaxy Note 7s started emitting smoke.
The decision to recall the device for a second time in a matter of weeks has fuelled expectations it will be scrapped altogether and sent Samsung’s share prices tumbling.
