Tesla sued Sweden’s Transport Agency on Monday over a strike by postal workers that has blocked delivery of license plates for Tesla cars, the latest escalation of a widening battle between Sweden’s labor unions and the U.S. manufacturer of electric vehicles.

A month ago, mechanics at seven Tesla-owned repair shops in Sweden walked off their jobs. Since then, hundreds of laborers from other industries across the country have joined in the action, aimed at getting Tesla to sign a collective bargaining agreement with the mechanics’ union, IF Metall.

Dockworkers, electricians, painters and postal employees have all joined the strike, refusing to provide the company with their services. Last week, some 50 metalworkers at a factory that produces aluminum parts for Tesla’s factory in Germany walked off the job.

On Nov. 20, postal workers joined the action, refusing to deliver any mail or packages to Tesla’s facilities, including the license plates.

That prompted Elon Musk, the carmaker’s chief executive, to call the widespread strikes “insane” in a post on X, formerly Twitter — his first public comment on the strikes. Although Sweden is a relatively small market for Tesla, and it makes no cars in the country, the company’s Model Y is a top-seller among Swedes.

On Monday, Tesla took legal action, filing complaints against the Transport Agency, which oversees production of the plates, and the postal company, PostNord. It argued that Tesla employees should be allowed to pick up the license plates from the agency, circumventing the postal workers.

In the lawsuit against the agency, Tesla argued that the authority has “a constitutional obligation to provide license plates to vehicle owners,” according to a copy issued by the Norrkoping District Court. A judge issued a temporary order on Monday requiring the agency to make the plates available to Tesla, pending a final ruling.

The withholding of license plates “cannot be described in any other way than as a unique attack on a company operating in Sweden,” the automaker said in the suit. It called for the district court to fine the agency 1 million kronor, or $95,400, unless it allowed Tesla to “retrieve license plates” within three days of the court’s decision.

The Transport Agency “does not share” Tesla’s view that it is failing to meet its obligation to produce the license plates for newly registered vehicles in Sweden, said Mikael Andersson, a spokesman for the agency.

But because the postal workers have joined in the strike targeting Tesla, they are not being delivered, Mr. Andersson said. “Therefore, Tesla has decided to have the issue tested in court, which is their right,” he said.

The Solna District Court, which is handling Tesla’s case against PostNord, rejected the carmaker’s request to be immediately allowed to collect 28 license plates in the postal company’s possession. A ruling in that case is not expected before next week.

Tesla did not respond to requests for comment.

Sweden has a long history of organized labor, and the right to strike is enshrined in the country’s constitution, which also allows a union in one sector to petition unions representing workers in other professions to stage targeted action against a company. Over the past month, hundreds of workers across the country have joined IF Metall in pressuring Tesla to come to the bargaining table.

Tesla has resisted efforts of its more than 127,000 employees around the globe to organize.

Christina Anderson contributed reporting.