Turn-about is fair play, it seems. Apple’s patent-infringement complaint seeking to block Nokia Oyj’s phone imports into the U.S. will be investigated by a U.S. trade agency, reports “Bloomberg” (http://www.bloomberg.com/apps/news?pid=conewsstory&tkr=AAPL%3AUS&sid=a4xrkt3A4eeI).

The U.S. International Trade Commission in Washington said yesterday it will consider the complaint filed last month and decide whether to ban the imports. Last month, Nokia filed yet another patent lawsuit against Apple, alleging that the company violates 10 of its US patents related mostly to smartphone technology. Also in January, Nokia filed a complaint with the United States International Trade Commission (ITC) alleging that Apple infringes Nokia patents in virtually all of its mobile phones, portable music players, and computers.

This followed — now play close attention — an Nokia complaint filed in October Nokia against Apple with the Federal District Court in Delaware, alleging that Apple’s iPhone infringes Nokia patents for GSM, UMTS and wireless LAN (WLAN) standards. Basically, Nokia claims that Apple isn’t paying licensing fees for the wireless technologies it uses in the iPhone, iPhone 3G and iPhone 3GS.

On Dec. 11, Apple filed a countersuit claiming that Nokia is infringing 13 Apple patents. “Other companies must compete with us by inventing their own technologies, not just by stealing ours,” said Bruce Sewell, Apple’s General Counsel and senior vice president.