Motorola, just days after being targeted in a patent suit by Microsoft, filed complaints against Apple on Wednesday alleging that the iPhone, iPad and other products infringe its patents.
The Motorola complaints allege that Apple's iPhone, iPad, iPod Touch and certain Macintosh computers infringe 18 patents "which relate to early-stage innovations developed by Motorola in key technology areas."
Motorola said its subsidiary, handset division Motorola Mobility, has filed complaints with the US International Trade Commission and courts in Illinois, where the company has its headquarters, and the southern state of Florida.
The patents relate to antenna design, wireless email, proximity sensing, software application management, location-based services and multi-device synchronization, Motorola said in a statement.
Motorola asked the Washington-based ITC to launch an investigation into Apple's alleged use of Motorola patents and bar the importation and sale of infringing products in the United States.
"Motorola has innovated and patented throughout every cycle of the telecommunications industry evolution," Kirk Dailey, Motorola Mobility's corporate vice president of intellectual property, said.
"We have extensively licensed our industry-leading intellectual property portfolio, consisting of tens of thousands of patents in the US and worldwide," Dailey said.
"After Apple's late entry into the telecommunications market, we engaged in lengthy negotiations, but Apple has refused to take a license," he said.
"We had no choice but to file these complaints to halt Apple's continued infringement," Dailey said.
Patent lawsuits are a regular occurrence among technology giants and Motorola's complaints against Apple come just days after US software giant Microsoft filed suit against Motorola.
Microsoft on Friday accused Motorola of violating its patents in mobile phones powered by Google's Android operating system.
Microsoft supplies its own mobile operating system to handset makers and is reportedly planning to unveil three Windows Phone 7 smartphones next week made by South Korea's Samsung and LG Electronics and Taiwan's HTC.
Apple is currently being sued by Finnish mobile phone giant Nokia for patent infringement and has fired back with a countersuit against Nokia.
HTC and Apple are also currently suing each other over patent claims involving Android-powered phones.
In June, Canada's Research in Motion, maker of the Blackberry, and Motorola reached a settlement to their long-running patent disputes.
Explore further: Uber ramps up safety efforts after criticism