Shares in Samsung have fallen after it delayed shipments of its latest smartphone - but without giving a detailed reason for the decision.
Samsung said: "Shipments of the Galaxy Note 7 are being temporarily delayed for additional quality assurance inspections."
There are reports in South Korea and the US of the Galaxy Note 7 "exploding" either during or just after charging.
However, it is unclear whether the delay is because of these reports.
Pictures and videos shared online depict charred and burnt handsets.
Shares fell as much as 3.5% during trade in Seoul before making a partial recovery to close 2% down on the day.
Sister company Samsung SDI told Reuters that while it was a supplier of Galaxy Note 7 batteries, it had received no information to suggest the batteries were faulty.
Catching fire
A YouTube user who says they live in the US uploaded a video of a Galaxy Note 7 with burnt rubber casing and damaged screen under the name Ariel Gonzalez on 29 August.
He said the handset "caught fire" shortly after he unplugged the official Samsung charger, less than a fortnight after purchasing it.
"I came home after work, put it to charge for a little bit before I had class, went to put it on my waist and it caught fire," he said.
He added that while he was unharmed, his carpet was burnt in the incident.
At least five other claims of phones "exploding" had been made by 24 August, according to the Korean news agency Yonhap News.
Further images of a burnt Galaxy Note 7 were uploaded to Kakao Story, a popular social media site in Korea, on 30 August.
A user wrote: "There was another explosion of the Galaxy Note 7. It was my friend's phone. A Samsung employee checked the site and he is currently in talks over the compensation with Samsung. You should use its original charger just in case and leave the phone far away from where you are while charging."
The post has since been deleted, according to Business Korea.
Samsung vs Apple
Rival Apple is due to hold an event on 7 September, where it is expected to announce its latest iPhone.
"The timing could not be worse for Samsung," said Roberta Cozza, research director at Gartner.
"Samsung was back on track with its premium phones after the Galaxy S7 earlier this year. If it plans on issuing a recall, it will have to be done quickly, as such issues can be very damaging.
"The Galaxy Note 7 was very well received when it was launched earlier this month, so this is a delicate moment."