China's Huawei Technologies Co. sued Motorola on Monday, accusing it of seeking to transfer confidential Huawei intellectual property information to Nokia Siemens Networks.
Motorola last year agreed to sell its wireless network business to NSN, a joint venture between Finland's Nokia and Germany's Siemens, for $1.2 billion.
Huawei asked a US District Court in Illinois, where Motorola has its headquarters, to block the transfer of Huawei-developed wireless and core network communications technology to NSN.
Motorola split into two companies - Motorola Mobility and Motorola Solutions on January 4.
The Huawei lawsuit for "misappropriation of trade secrets, copyright infringement, and breach of contract" named Motorola Mobility, Motorola Solutions and NSN as defendants.
"Since 2000, Huawei and Motorola have had a cooperative relationship in the radio access network and core network businesses, where Motorola has resold Huawei wireless network products to customers under the Motorola name," Huawei said.
"During this period, Motorola was provided with products and confidential Huawei IP developed by Huawei's team of more than 10,000 engineers," it said.
"Since the July 2010 announcement by NSN of its purchase of Motorola's wireless network business, Huawei has tried to ensure that Motorola does not transfer this confidential information to NSN," Huawei said.
The Chinese telecom maker said Motorola has "not responded with assurances that it will prevent disclosure of that information to NSN."
"If Huawei's proprietary commercial property and information is transferred to a third party, Huawei will suffer irreparable commercial damage," it said.
Motorola Solutions said it was reviewing the suit.
Motorola sued Huawei in July, alleging it used Motorola employees to secure detailed confidential information about its cellular network equipment.
NSN said last month that its purchase of Motorola's wireless network infrastructure assets would be delayed pending approval from Chinese regulators.
On December 15, the European Commission gave the green light to the transaction. The deal has also received the approval of regulators in the United States.