Striking workers disrupted production at Airbus factories in France for four hours on Thursday in a dispute over restructuring, unions said.

The strike was called after Airbus dropped plans to sell some of its factories in Germany to an outside investor but pressed ahead with plans to sell two of its three factories in France.

French Unions say French and German plants should be treated equally and have asked to meet Louis Gallois, EADS chairman, as soon as possible. They are also demanding that the plans to sell be withdrawn.

"Certain sites have been completely blocked. At others we only set up check-point barriers, and the employees are free to enter the factories," said Marina Lensky, senior delegate of the CFTC union.

Airbus declined comment.

"We will let the strike speak for itself," said Jacques Rocca, director of communication at Airbus France.

The four hour strike started at 7:30 local time (0530 GMT) and was backed by five major unions.

Output was disrupted at Airbus headquarters in Toulouse as well as the two plants due to be sold to aerospace supplier Latecoere - St Nazaire-Ville in western France and Meaulte in northern France.

500 employees gathered in front of the Bouguenais site near Nantes, 300 at the St-Nazaire site and 800 at Gron in Loire-Atlantique in the west of France, according to the unions.

Union CGT delegate at Meaulte, Xavier Petrachi, said the strike there would last "all day Thursday, and without doubt, Friday as well".

"This is only the first warning," said Jean-Claude Gangard, a trade unionist from French union "Force ouvriere".

Airbus is cutting jobs and selling factories to cut costs in the face of a weak dollar and to raise outside investment in new composite materials.

Parent company EADS said on Sunday it would hive off three German factories -- Varel, Nordenham and Augsburg -- into an EADS-owned subsidiary after failing to sell them to the preferred buyer MT Aerospace.