Nikola filed the lawsuit Tuesday in Arizona federal court. The lawsuit claims that Tesla’s electric semi, which was unveiled in November 2017, infringes on several of its patents, including Nikola’s mid-entry door, fuselage, and wrap windshield that is designed to give the driver an unobstructed view of the road.

Nikola Motor is designing and building its own driverless, hydrogen fuel cell–powered Class 8 truck. The company posted a design of its Nikola One freight truck in May 2016. The company unveiled the Nikola One in December 2016. It is also developing a Nikola Two day-cab, which will begin testing in fall 2018. It’s expected to go into full production in 2021.

In January, Nikola Motor announced plans to build a $1 billion hydrogen-electric semi truck factory in a suburb of Phoenix.

“It’s patently obvious there is no merit to this lawsuit,” a Tesla spokesperson said in an emailed statement.

Four months after Nikola first published its design, Aaron Hoyos, a recruiter for Tesla, reached out to Nikola’s chief engineer Kevin Lynk, the lawsuit alleges. In that email, the lawsuit alleges that Hoyos told Lynk that “Tesla is building a new team to focus on development heavy Class A trucks” and said his background would be a “good fit.”

Tesla released a teaser image of its Tesla Semi in April 2017. Six months later, just days before Tesla would reveal its Tesla Semi truck at a splashy event, Nikola sent a letter demanding the company not proceed with the unveiling until the patent infringement was resolved, the lawsuit says. Nikola says in the lawsuit that Tesla never responded.

The lawsuit highlights an increasingly heated competition in the trucking industry. Dozens of other companies, from truckmakers like Daimler, Navistar, and Volkswagen to startups like Peloton and Embark as well as Uber’s Otto and Waymo, the erstwhile Google self-driving project, are pursuing what they believe is the next generation of trucking.