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EasyJet cabin crews in Spain will go on strike over their pay for three days next week.
The USO union in Spain said the industrial action would take place from Wednesday 25 June to Friday 27 June.
It said more than 650 flight attendants – based in Alicante, Barcelona, Malaga and Palma de Mallorca – could be involved.
However, the airline said it intended to operate normally and hoped to avoid any disruption.
The union said easyJet cabin crews earn much less in Spain than in other countries.
It added that the aim of the strike was "to level the crews' working and wage conditions in Spain with the ones at other bases of the company in Europe".
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A spokesperson for the airline said it would do everything possible to minimise the impact of the strikes.
They added that easyJet employed crews in eight different countries "on local terms and conditions".
Regulations in Spain compel airline workers to provide a minimum level of service during industrial action to limit disruption.
