About 130 workers affiliated with IF Metall began a strike on Oct. 27, sparking sympathy strikes - a solidarity tactic by unaffected workers - from dockworkers, cleaners and car dealerships.

Sympathy strikes are generally legal in the Nordic countries, in a stark contrast to the U.S. where such actions are largely prohibited.

In the 1990s, American toy company Toys "R" Us signed a collective agreement with its 130 Swedish employees after a three-month strike that was also accompanied by sympathy strikes and blockades.

Here is an overview of sympathy actions that are adding pressure on Tesla by potentially disrupting its supply chain in Sweden, where Tesla's Model Y is the most sold new car so far this year:

SWEDEN

Sweden's transport workers' union pledged in November to block loading and unloading of Tesla cars across the country's ports. A dockworkers' union also said it would not handle Tesla cars in Swedish harbours from Nov. 17.

Seko, which represents service and communications workers, on Nov. 20 started a blockade against delivery and collection of mail and parcels at Tesla's Swedish workplaces by logistics firms PostNord and CityMail, cutting the EV-maker's access to license plates from the country's transport authority.

The union of civil servants said its members at PostNord, owned by the Swedish and Danish states, would pause deliveries to Tesla from Nov. 21.

The electricians' union vowed in November to block electrical reparation works at Tesla facilities and charging stations, and painters union warned it planned to stop painting of Tesla cars.

The building maintenance workers' union halted all work related to the automaker from Nov. 17, while a building workers' union pledged to halt maintenance and construction work at Tesla service workshops.

Unionised workers at Hydro Extrusions, a subsidiary of Norwegian aluminium and energy company Hydro, stopped work on Tesla car products from Nov. 24. The workers are members of IF Metall.

Sweden's musicians' union said on Nov. 14 it would block some music from Tesla cars' media systems.

Some Swedish pension funds have urged Tesla to sign the agreement with the union, but so far held off selling shares.

NORWAY

Norway's largest private sector labour union said on Dec. 6 it would start blocking transit shipments of Tesla cars meant for the Swedish market from Dec. 20 unless the EV-maker reaches an agreement with IF Metall.

The union said it intended to send a "clear signal to Tesla" and do what was necessary to ensure that any vehicle shipments via Norway to Sweden were blocked, but declined to say exactly which measures it might take.

DENMARK

Danish dockworkers' union said on Dec. 5 it would not unload or transport cars made by Tesla for Swedish customers.

PensionDanmark, one of Denmark's largest pension funds, said on Dec. 6 it had decided to sell its holdings in Tesla over the automaker's refusal to enter into agreements with labour unions.

FINLAND

Finnish transport workers' union said on Dec. 7 its dockers would not load Tesla vehicles and components destined to Sweden in all Finnish ports from Dec. 20.