Smartphone giant Samsung has reportedly stopped production of its Note 7 phone amid claims that replacement devices are still at risk of catching fire.
News agencies reported Samsung had temporarily halted production after talks with safety regulators.
Samsung told the BBC it was "adjusting the production schedule to ensure quality and safety matters".
The company has been forced to issue new models of the smartphone following complaints of faulty batteries.
It issued a recall of the Galaxy Note 7 in September and later assured customers that the fixed devices were safe.
But there have now been several reports of replacement phones starting to emit smoke.
'No longer exchanging'
In a further blow, two US mobile networks have stopped replacing or selling the phone.
The AT&T and T-Mobile networks said they would no longer replace the devices in the US, while the latter said it would halt all sales of the phone.
"While Samsung investigates multiple reports of issues, T-Mobile is temporarily suspending all sales of the new Note 7 and exchanges for replacement Note 7 devices," T-Mobile said on its website.
Meanwhile, AT&T said: "We're no longer exchanging new Note 7s at this time, pending further investigation of these reported incidents." It advised customers to exchange them for other devices.
Samsung said in a statement last month that the issue of overheating was caused by a "rare" manufacturing error that resulted in the battery's "anode-to-cathode [negative and positive electrodes]" coming into contact.
In an update on Monday, Samsung said it understood the concerns of carriers and consumers about the newly released replacement Note 7 devices.
"We continue to move quickly to investigate the reported case to determine the cause and will share findings as soon as possible," Samsung said.
"If we conclude a product safety issue exists, we will work with the CPSC (US Consumer Product Safety Commission) to take immediate steps to address the situation."
Shares in Samsung Electronics closed down 1.5% in Seoul.
Eric Schiffer, a brand strategy expert at Reputation Management Consultants, said the company needed to take action to limit the harm to its image.
"If the Note 7 is allowed to continue, it could lead to the single greatest act of brand self-destruction in the history of modern technology," he said.
"Samsung needs to take a giant writedown and cast the Note 7 to the engineering hall of shame next to the Ford Pinto."
In 1977, the Pinto was the subject of a then-record US recall to address safety concerns.