German pilots working for Ryanair have voted to strike as they push for collective labour agreements at Europe's largest low-cost carrier, their union said on Monday.

Ryanair management had met with the Vereinigung Cockpit (VC) pilot union in Frankfurt last week. VC said the talks ended without the progress they had hoped for.

The union is giving Ryanair until Aug. 6 to make another offer, VC said in a statement, announcing it would host a press conference on Aug 8 to discuss its next steps.

Ryanair said in December it would recognise unions for the first time but has been struggling to reach agreements with some. It cancelled flights after strikes last week by Dublin-based pilots and stoppages by cabin crew in Italy, Spain, Portugal and Belgium.

It also said it planned to shift aircraft and jobs out of Dublin, saying that strikes by Irish pilots had harmed bookings.

VC said 96 percent of Ryanair pilots in Germany voted in favour of strike action. It will give at least 24 hours' notice of any strikes, it said.

"Ryanair has been playing for time in the negotiations since January," VC said. "If the signal given by this vote is not taken seriously, then strikes - such as in other European countries - are inevitable."

German pilots were the first to strike at Ryanair last year, but the disruption was limited.

Ryanair did not immediately respond to a request for comment.