The U.S. International Trade Commission added yet another tech patent infringement investigation to its plate now that it plans to look into Nokia based on a complaint by Apple. If the agency finds Nokia is infringing on Apple-owned patents with its cell phones, it could block the handsets from being imported into the U.S., according to Bloomberg.

Apple and Nokia have been locked in a battle over alleged patent infringement issues for several months. Nokia filed its own ITC complaint in 2009, along with patent infringement lawsuits in 2009 and at the beginning of the year, claiming the majority of Apple's products, including the MacBook lineup and the iPhone, violate wireless tech-related patents it owns.

Apple fired off its own lawsuit against Nokia at the end of 2009 alleging Nokia is violating 13 patents it owns. At the time of the filing, Apple's General Counsel and senior vice president, Bruce Sewell, commented "Other companies must compete with us by inventing their own technologies, not just by stealing ours."

The ITC previously agreed to look into Nokia's complaints against Apple, but hasn't said if it plans to run the investigations concurrently.