(Bloomberg) -- Airbus SE workers have begun a series of walkouts at German factories, escalating a dispute over the planemaker’s move to restructure aircraft-parts operations in the country. 

The IG Metall union said that so-called warning strikes were planned over three days through Saturday at Premium Aerotec division sites in Varel, Nordenham and Augsburg, along with a one-day action in Bremen Friday. Further walkouts were called at Airbus locations in Hamburg and Stade from Friday to Sunday. 

Labor leaders oppose Airbus’s plan to streamline subsidiaries that make wing and fuselage sections, and protested in September with a single day of strikes and rallies. The restructuring, first announced in April, involves the creation of new in-house companies around Premium Aerotec and France-based Stelia Aerospace, while a detailed-parts unit will be hived off and sold.

In a statement, IG Metall said Toulouse, France-based Airbus isn’t prepared to reach a fair package for all employees and locations. 

“The only thing left for us is to increase the pressure and to fight with further warning strikes,” said Daniel Friedrich, a union official in Hamburg. “If we don’t come to a solution in a timely manner, we will run into a major conflict.”

The conflict threatens to disrupt a ramp-up in narrow-body jet production that’s already being slowed by challenges in obtaining parts from suppliers. Airbus has targeted output of 600 aircraft this year, and was still about 100 short as of late November, Bloomberg has reported.

Airbus Has Five Weeks to Deliver 100 More Jets and Hit 2021 Goal

An Airbus spokesman said that bringing structural assembly in house will bolster its jetliner business and see 2 billion euros ($2.3 billion) invested in German sites by 2025, while the detail-parts operation will have better growth opportunities once sold.

He said the company regrets that no agreement could be reached with unions after months of negotiations.

“The times don’t justify such strike action,” Airbus Chief Executive Officer Guillaume Faury said in a memo to staff seen by Bloomberg. “The reasons given are incomprehensible and the interests of the company and its employees are not being respected.”

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