Warning strikes by the UFO cabin crew union disrupted some flights by Lufthansa in Frankfurt and Berlin early on Wednesday, the airline and the union said.

The six-hour walkout starting at 0600 local time (0500 GMT) follows similar action last week as the union presses demands for higher pay.

A Lufthansa spokesman said some flights were delayed and the union said some were cancelled but they were not more specific.

UFO is pushing for a 15 percent wage increase for its 16,000 members. Lufthansa had lifted its offer to a rise of up to 10 percent. The package also includes better work conditions and profit sharing.