A federal agency has banned US imports of new mobile phones made with Qualcomm semiconductors due to a patent row.
The ruling will affect forthcoming handsets made by Motorola and Samsung, in addition to network providers such as Verizon, Sprint Nextel and AT&T.
Qualcomm, which is appealing against the ruling, said the ban could prevent imports of tens of millions of phones.
The firm's computer chips are used to access data services such as internet downloads and video calls.
'Impact on consumers'
The ruling by the US International Trade Commission found that Qualcomm had violated patents owned by rival company Broadcom.
"We believe the commission has overstepped its statutory boundaries and has not afforded due process to manufacturers and operators," said Qualcomm chief executive Paul Jacobs.
"If [the ruling] stands, it will have a negative impact on consumers."
Analysts say that if the ruling remains it could push up the price of mobile phones in the US as makers have to switch to rival chip providers.
Some add that it may also be a boost to Apple's forthcoming iPhone, which does not use Qualcomm chips, as it will delay rival new offerings from Motorola and Samsung.
Verizon said it had asked a federal court to block the commission's order, and that it was also calling on the White House to veto the ruling.