BERLIN (AP) — A German union representing cabin crew has called members at several Lufthansa subsidiaries out on strike — a walkout that was extended by 13 hours at short notice.

The UFO union is locked in a long-running dispute with the company over pay and the legal status of the union, which has been engaged in an internal leadership struggle.

UFO initially called on members at Eurowings, Germanwings, Lufthansa CityLine and SunExpress to walk out from 5 a.m. to 11 a.m. Sunday, but on Sunday morning extended the strike to midnight, accusing the company of turning up pressure on cabin crew not to participate. Lufthansa itself wasn't affected by Sunday's strike.

Some flights were canceled, but it wasn't immediately clear how many.