HTC fired off another shot yesterday in its ongoing legal tussle with Apple over patents used in its Android-based smartphones, when it filed a new patent infringement complaint with the U.S. International Trade Commission (ITC).

The suit alleges that Apple's Mac computers, as well as its iPhone, iPad and iPod products, violated three of HTC's patents.

The patents at issue, U.S.  Patent Nos. 7,417,944, and 7,672,219 and 7,765,414, cover Wi-Fi networking capabilities for multiple devices and technology that integrates the functions of a personal digital assistant with a cell phone.

"This is the 3rd case before the ITC in which Apple is infringing our intellectual property," HTC general counsel Grace Lei said in a statement. "Apple needs to stop its infringement of our patented inventions in its products."

Apple could not be immediately reached for comment.

Apple first sued HTC last year over 10 patents, setting off an escalating legal spat that has spread to the United Kingdom, where HTC filed a complaint against Apple in late July.

HTC's latest legal salvo comes one month after the ITC ruled that it had violated two of Apple's patents. HTC has vowed to appeal the ruling.

HTC and Apple are both fighting a number of other legal battles over patents used in their respective wireless devices. Apple recently scored a victory over Samsung in Germany, where a court granted an injunction against the company's Android-based Galaxy Tab tablet.

Patents have become progressively more important to stakeholders in the wireless industry amid increasingly aggressive litigation over intellectual property. Patents were a key factor in Google's recent $12.5 billion purchase of Motorola Mobility, announced Monday.