The Chinese manufacturer of batteries used in Samsung's recalled Note 7 smartphones said on Monday its battery is not the cause of the phone's explosive tendency.
"Test results show that the fire is not directly connected to the battery produced by our company," parts manufacturer Amperex Technology Limiter (ATL) said.
Samsung had previously said that initial investigations showed faulty batteries as the cause of the fire hazard.
ATL said its tests, which followed the first media reports of exploding Samsung phones in China, showed "external factors" outside of its battery were the cause of the fires.
Launched shortly before the unveiling of Apple's new iPhone model, the Galaxy Note 7 smartphone was promptly taken off the market and recalled after reports emerged of the device exploding.
Several international airlines announced bans on passengers using and charging the smartphone on planes following advice from the US Federal Aviation Administration.
According to the US consumer protection authorities, around 1 million users in the US are impacted by the recall, amid 92 reported incidences of the model catching fire. Media reports have put the worldwide number of Samsung phones to be recalled at 2.5 million.