Taiwanese smartphone maker HTC has hit back at Apple with a complaint to the Federal Trade Commission (FTC) that seeks to halt the sale of iPhones, iPods and iPads made outside the US.
The move comes less than three months after Apple sued HTC for allegedly violating 20 patents relating to the iPhone's user interface, underlying architecture and hardware.
HTC claims Apple is infringing the patents of three phone directories and two relating to power management.
"We are taking this action against Apple to protect our intellectual property, our industry partners, and most importantly our customers who use HTC phones," Jason Mackenzie, vice-president of HTC's North American operations, said in the statement.
But US analysts have dismissed HTC's complaint as little more than a tactic to delay Apple's case against the company, according to reports.
Observers said the lawsuits are likely to increase tension between Apple and Google as they ramp up their fight for bigger shares of the smartphone market.