SAO PAULO (AP) — Metalworkers at Brazilian aircraft maker Embraer have started a strike and halted production at the company’s main plant outside metropolitan Sao Paulo.

The union of metalworkers of the city of Sao Jose dos Campos said in a statement on Tuesday that the strike could last indefinitely. The union is seeking a raise of nearly 6.4 percent, and says that would be the first pay hike in four years that outpaces inflation.

Brazil’s government recently agreed to sell a controlling stake of Embraer’s commercial aircraft arm to American giant Boeing, though that isn’t an issue in the strike.

Embraer hasn’t replied a request for comment from The Associated Press.

Union director Herbert Claros said Embraer’s offers to avoid the strike were disrespectful.