Huawei has filed two lawsuits against Verizon (VZ  ) alleging the U.S. carrier infringed patents held by the Chinese telecoms giant.

In the lawsuits, Huawei is claiming that Verizon infringed on 12 of its U.S. patents. Huawei claims it is only taking action after months of negotiations with Verizon.

Huawei has a small presence in the U.S., but American companies like Verizon will use Huawei's patent technology. The reason is Huawei holds over 87,000 patents globally with 11,000 of those being in the U.S.

Verizon buys equipment that uses Huawei's technology from other vendors. According to Huawei, some of the equipment doesn't have cross-license agreements.

"Since 2015, Huawei has received more than $1.4 billion dollars in patent license fees," the company says in a statement. "To date, it has also paid over $6 billion dollars for the legitimate use of patented technologies developed by industry peers. 80 percent of these license fees have gone to companies in the United States."

"Verizon's products and services have benefited from patented technology that Huawei developed over many years of research and development," adds Huawei's chief legal officer Song Liuping. "For years now we have successfully negotiated patent license agreements with many companies. Unfortunately, when no agreement can be reached, we have no choice but to seek a legal remedy."

Huawei has been at odds with the U.S. since last year due to the U.S.-China trade war. The Trump administration has argued that installing any of the company's equipment in U.S. networks would allow Chinese intelligence agents to wiretap sensitive U.S. communications. Huawei has consistently denied the allegations.

The U.S. has called for its allies to reject Huawei's 5G equipment, but the U.K. decided to allow Huawei to work on parts of its 5G infrastructure.

Despite the prolonged American campaign against its business, Huawei managed to increase sales to 850 billion yuan ($122 billion) in 2019, up 18% from the previous year.