Ryanair has halted talks with two Spanish unions over a salary hike, the unions said, amid threats the low-cost airline's cabin crew could go on strike in several European countries during the summer season.

Europe's biggest budget airline walked away from the talks thios week arguing the strike threat by European unions showed a lack of commitment to dialogue, Spanish unions USO and STCPLA said in a joint statement.

They accused Ryanair of acting in bad faith and said they sought to return to the negotiating table.

Ryanair did not immediately respond to a request for comment.

Seven unions from Italy, France, Portugal, Belgium and Spain issued a statement in May warning that Ryanair's cabin crew in those countries could launch a strike this summer if the airline did not offer a "meaningful response" to their demands for better working conditions.

The threat comes as the airline sector hopes to recover this summer from the impact of the pandemic.

Ryanair's Group Chief Executive Michael O'Leary said in May bookings looked very strong for the summer and the load factor should gradually rise to 94-95% in June-August, practically reaching pre-COVID-19 pandemic levels.

Portugal's union of civil aviation staff SNPVAC said in May after meeting other unions in Brussels that Ryanair acted as if "European and national legislation can be negotiated". It complained that crew members work without access to drinking water on board and have no local support from human resources.