HTC has filed a countersuit against Apple with the U.S. International Trade Commission (ITC) alleging that the company’s iPhone, iPad and iPod devices violate five of its patents.

Apple filed a similar complaint against HTC in early March alleging the company had violated 20 patents related to a device’s user interface. The ITC launched an investigation into the matter on March 31.

“…HTC believes the industry should be driven by healthy competition and innovation that offer consumers the best, most accessible mobile experiences possible,” said HTC North America Vice President Jason Mackenzie in a statement. “We are taking this action against Apple to protect our intellectual property, our industry partners, and most importantly our customers that use HTC phones.”

HTC and Apple have both asked the ITC to ban importation of each other’s respective products implicated in the complaints.

The ITC is targeting Oct. 6, 2011, as the date by which it expects to issue a ruling on the HTC/Apple spat. Patent infringement cases are often followed by years of legal wrangling.