In an escalation of the patent infringement war, Microsoft filed a formal complaint against Motorola Mobility with the European Commission on Wednesday, accusing Motorola of stifling competition with heavy-handed patent enforcement, the Associated Press (AP) reported.

Microsoft’s filing comes close on the heels of last week’s similar action against Motorola by Apple, the AP noted, adding that both actions followed a series of lawsuits filed by Motorola in Europe and the U.S. alleging that products offered by Apple and Microsoft contain Motorola’s patented wireless connectivity and video streaming technology without permission.

According to the AP, Microsoft contends that Motorola is demanding excessive fees for the use of its patented technology. "We have taken this step because Motorola is attempting to block sales of Windows PCs, our Xbox game console and other products," Dave Heiner, Microsoft's deputy general counsel, wrote in a blog post. “Motorola is on a path to use standard essential patents to kill video on the Web, and Google as its new owner doesn’t seem to be willing to change course,” he added.

The New York Times noted that the new litigation represents yet another round of patent disputes between Microsoft and Internet giant Google, which is currently completing its $12.5 billion acquisition of Motorola. The Times noted that Joaquín Almunia, the E.U. competition commissioner, has indicated that patent abuses will be a high-priority matter for the E.U. Though Almunia has approved Google’s acquisition of Motorola, he warned the company that the E.U. may punish “actions by Motorola in the past” and “future action by Google” regarding patent enforcement. The U.S. Justice Department has also expressed concern over Google and Motorola’s frequent resort to litigation to enforce patent rights, AP said.

Patent issues are a critical concern for worldwide technology players. Certain patented technology anchors accepted industry standards that permit products from different manufacturers to communicate and use the same 3G and wireless networks. The AP notes that the E.U. requires those owning patents for industry standards technology to extend the use of those patents to other company at a reasonable rate. According to the AP, Microsoft claims that Motorola’s wants as much as 2.25 percent of the price of certain Microsoft products for use of its industry standard patents. In an example cited by Heiner in his blog post, Motorola is requesting royalties of $22.50 for a laptop priced at $1,000 for the use of 50 patents relating to H.264 video compared to a total royalty charge of two cents requested by 29 companies owning 2,300 other patents required for H.264.

"If every firm priced its standard essential patents like Motorola, the cost of the patents would be greater than all the other costs combined in making PCs, tablets, smartphones and other devices," Heiner wrote in his blog post. "Obviously, this would greatly increase the prices of these devices for consumers."