(Reuters) - BlackBerry Ltd BB.TO on Tuesday filed a patent infringement lawsuit against Facebook Inc FB.O and its WhatsApp and Instagram apps, arguing that they copied technology and features from BlackBerry Messenger.

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Litigation over patent infringement is part of BlackBerry Chief Executive John Chen’s strategy for making money for the company, which has lost market share in the smartphone market it once dominated.

“Defendants created mobile messaging applications that co-opt BlackBerry’s innovations, using a number of the innovative security, user interface, and functionality enhancing features,” Canada-based BlackBerry said in a filing with a Los Angeles federal court.

“Protecting shareholder assets and intellectual property is the job of every CEO,” BlackBerry spokeswoman Sarah McKinney said in an email. However, she noted that litigation was “not central to BlackBerry’s strategy.”

The lawsuit followed years of negotiation and BlackBerry has an obligation to shareholders to pursue appropriate legal remedies, she added.

Facebook Deputy General Counsel Paul Grewal said in a statement that the company intended to fight the lawsuit.

“Blackberry’s suit sadly reflects the current state of its messaging business,” Grewal said. “Having abandoned its efforts to innovate, Blackberry is now looking to tax the innovation of others.”

BlackBerry is trying to persuade other companies to pay licensing royalties to use its trove of more than 40,000 global patents on technology including operating systems, networking infrastructure, acoustics, messaging, automotive subsystems, cybersecurity and wireless communications.

BlackBerry is also selling cybersecurity software for self driving cars.

BlackBerry sued Nokia Corp in February 2017, alleging infringement of patents relating to 3G and 4G wireless communications technology. That case is still pending in federal court in Delaware.

Last year Qualcomm Inc QCOM.O agreed to pay BlackBerry $940 million to resolve arbitration over royalty payments.

In October 2017 BlackBerry announced a confidential settlement with Blu Products Inc, a Florida-based maker of low-cost mobile devices it had also sued for patent infringement.