The U.S. International Trade Commission has decided to investigate smartphones from Taiwan's HTC based on Apple's claims of patent infringement.
Apple filed the patent infringement charges with the ITC, as well as with the U.S. District Court in Delaware, in early March. The complaints make frequent reference to Android, Google's operating system that HTC is using in many of its touch-screen phones. Apple has said the products infringe 20 patents related to the iPhone's user interface and hardware.
On Wednesday, the ITC said that one of its administrative law judges will hold an evidentiary hearing to look into Apple's complaint. The ITC now has 45 days to set a target date for completing the investigation.
Apple has asked the ITC to forbid HTC from selling the phones in the U.S.
HTC has vehemently denied infringing Apple's patents, and Google has said it will stand by its phone-making partners.
Apple warned when it introduced the iPhone that it had hundreds of patents related to the device and would aggressively defend them.
But while there have been many copycats since the first iPhone launched in 2007, there have been few lawsuits. Some observers wonder why Apple decided to act now against HTC, and have speculated that the charges are really aimed at Google, which has had an increasingly strained relationship with Apple.
The two companies historically did not compete, but with the introduction of Android, Google is directly competing with the iPhone.
Apple is also engaged in a patent battle with Nokia, the number-one handset maker in the world. Nokia initiated that dispute when it filed a patent infringement suit against Apple in October.